Systems and methods to gather and analyze electroencephalographic data

ABSTRACT

Example devices are disclosed herein that include a first elongated band coupled to a first housing to be located on a first side of a head of a subject and a second housing to be located near a second side of the head of the subject, the first elongated band comprising a first set of electrodes. The example device also includes a second elongated band coupled to the first housing and to the second housing, the second elongated band comprising a second set of electrodes. In addition, the device includes a third elongated band coupled to the first housing and to the second housing, the third elongated band comprising a third set of electrodes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent arises from a continuation of U.S. application Ser. No.15/880,236 (now U.S. Pat. No. 10,779,745), titled “SYSTEMS AND METHODSTO GATHER AND ANALYZE ELECTROENCEPHALOGRPHIC DATA,” filed Jan. 25, 2018,which is a continuation of U.S. application Ser. No. 14/746,440 (nowU.S. Pat. No. 9,907,482), titled “SYSTEMS AND METHODS TO GATHER ANDANALYZE ELECTROENCEPHALOGRPHIC DATA,” filed Jun. 22, 2015, which is acontinuation of U.S. application Ser. No. 13/728,900 (now U.S. Pat. No.9,060,671), titled “SYSTEMS AND METHODS TO GATHER AND ANALYZEELECTROENCEPHALOGRPHIC DATA,” filed Dec. 27, 2012, which claims priorityto U.S. Provisional Application No. 61/684,640, titled “SYSTEMS ANDMETHODS TO GATHER AND ANALYZE ELECTROENCEPHALOGRPHIC DATA,” filed Aug.17, 2012. U.S. application Ser. No. 15/880,236; U.S. application Ser.No. 14/746,440; U.S. application Ser. No. 13/728,900; and U.S.Provisional Application No. 61/684,640 are hereby incorporated by thisreference in their entireties.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to neurological andphysiological monitoring, and, more particularly, to systems and methodsto gather and analyze electroencephalographic data.

BACKGROUND

Electroencephalography (EEG) involves measuring and recording electricalactivity resulting from thousands of simultaneous neural processesassociated with different portions of the brain. EEG data is typicallymeasured using a plurality of electrodes placed on the scalp of a userto measure voltage fluctuations resulting from this electrical activitywithin the neurons of the brain. Subcranial EEG can measure electricalactivity with high accuracy. Although bone and dermal layers of a humanhead tend to weaken transmission of a wide range of frequencies, surfaceEEG also provides useful electrophysiological information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of an example headset having aplurality of adjustable bands in accordance with the teachings of thisdisclosure.

FIG. 2 is a right side view of the headset of FIG. 1.

FIG. 3 is a left side view of the headset of FIG. 1.

FIG. 4A is a perspective view of the headset of FIG. 1 in an exampleorientation.

FIG. 4B is a perspective view of the headset of FIG. 1 in anotherexample orientation.

FIG. 5 is a perspective view of an example adjustable band or spine ofthe headset of FIG. 1.

FIG. 6 is an enlarged view of an end of the example spine of FIG. 5.

FIG. 7 is a cross-sectional view of the example spine of FIG. 5.

FIG. 8A is a circuit diagram for an example EEG system.

FIG. 8B is a circuit diagram for an example EEG system with wetelectrodes.

FIG. 8C is a circuit diagram for an example EEG system with dryelectrodes in accordance with the teachings of this disclosure.

FIG. 9 is a schematic view of a top of a head illustrating exampleelectrode and ground placement locations.

FIG. 10 is an enlarged view of an example adjustment mechanism shown onthe headset of FIG. 1.

FIG. 11A is a perspective view of an example electrode of FIGS. 1-7.

FIGS. 11B and 11C are front views of two alternative example electrodedesigns.

FIG. 11D is a perspective view of an example central electrode arrayplate.

FIG. 12A is a block diagram of an example switching circuit.

FIG. 12B is a graphical representation of averaging of multiple channelsof data.

FIG. 13A is a cross-sectional view of an example electrode in contactwith a scalp of a user.

FIG. 13B is a cross-section view of an alternative example electrode incontact with a scalp of a user.

FIG. 14 is a circuit diagram for an example electrode.

FIG. 15 is a perspective view of an alternative band or spine and analternative electrode constructed in accordance with the teachings ofthis disclosure.

FIG. 16 is an exploded view of the example electrode of FIG. 15.

FIG. 17 is an exploded view of another example snap electrodeconstructed in accordance with the teachings of this disclosure.

FIG. 18 is a perspective view of another example electrode constructedin accordance with the teachings of this disclosure.

FIG. 19A is a perspective view of another example electrode constructedin accordance with the teachings of this disclosure.

FIG. 19B is a cross-sectional view of the example electrode of FIG. 19A.

FIG. 20 is a perspective view of an example mold used for manufacturingan example spine.

FIG. 21 is a perspective view of an example spine after manufacturing inthe example mold of FIG. 20.

FIGS. 22A-22J are perspectives views of a user's head and example areasfor electrode contact.

FIG. 23 is a perspective view of another example headset constructed inaccordance with the teachings of this disclosure and having a pluralityof bands with electrode tips.

FIG. 24 is a bottom view of the example headset of FIG. 23 and a USBconnection port.

FIG. 25 is a perspective view of the example headset of FIG. 23 on a USBbase stand.

FIG. 26 is a back side view of the example headset of FIG. 23.

FIG. 27 is a top side view of the example headset of FIG. 23.

FIG. 28 is a right side view of the example headset of FIG. 23.

FIG. 29 is a bottom perspective view of the example headset of FIG. 23.

FIG. 30 illustrates an exploded view of example layers of an exampleheadset.

FIG. 31 is an exploded view of the example circuit housing of FIG. 30.

FIGS. 32A-32D are exploded views of an example electrode connector usedin the example headset of FIG. 23.

FIG. 33 is a side view of the example electrode connector of FIGS.32A-32D in a partially assembled state.

FIG. 34 is a perspective view of another example headset constructed inaccordance with the teachings of this disclosure.

FIG. 35 is a perspective view of an adjustment knob for the exampleheadset of FIG. 34.

FIG. 36 is a block diagram of an example circuit from the headset inFIGS. 1, 23 and/or 34.

FIG. 37 is a block diagram of an example manner of implementing theprocessor and signal selector of FIGS. 1-7 and 12.

FIG. 38 is a block diagram of an example manner of implementing theheadset(s) of FIGS. 1, 23 and/or 34 with additional physiological senorsystems.

FIG. 39 is a block diagram of an example manner of implementing theprocessing and conditioning of FIGS. 1, 23 and 34.

FIG. 40 is a flow chart representing an example method of analyzing EEGdata in accordance with the teachings of this disclosure.

FIG. 41 is a flow chart representing an example method of improving EEGsignal quality in accordance with the teachings of this disclosure.

FIG. 42 is a flow chart representing an example method of conductingat-home patient monitoring/treatment in accordance with the teachings ofthis disclosure.

FIG. 43 is a flow chart representing an example method of processing auser's attention to a media and desire to control a device in accordancewith the teachings of this disclosure.

FIG. 44 is a flow chart representing an example method of gathering andanalyzing electroencephalographic data in accordance with the teachingsof this disclosure.

FIG. 45 illustrates an example processor platform that may execute oneor more of the instructions of FIGS. 40-44 to implement any or all ofthe example methods, systems and/or apparatus disclosed herein.

DETAILED DESCRIPTION

Certain examples are shown in the above-identified figures and disclosedin detail below. In describing these examples, like or identicalreference numbers are used to identify the same or similar elements. Thefigures are not necessarily to scale and certain features and certainviews of the figures may be shown exaggerated in scale or in schematicfor clarity and/or conciseness. Additionally, several examples have beendescribed throughout this specification.

Biological cells and tissues have electrical properties that can beread, which provide information regarding the functioning of the cell ortissue. Various types of electrophysiological techniques have beendeveloped to measure electrical signals from a body. For example,electrocardiography (ECG or EKG) measures electrical activity in aheart. Electroencephalography (EEG) measures electrical activity in abrain. Electrocorticography (ECoG) measures electrical activity usingelectrodes placed directly on an exposed surface of a brain to recordelectrical activity in a cerebral cortex. Electromyography (EMG)measures electrical activity in a muscle. Electrooculography (EOG)measures the resting potential of a retina, and electroretinographymeasures electrical responses of retinal cells. These and/or otherelectrophysiological signals are important in the treatment, diagnosisand monitoring of many health conditions.

EEG data is indicative of electrical activity of neurons includingneural depolarization in the brain due to stimuli of one or more of thefive senses (evoked activity) as well as from thought processes(spontaneous activity) generates electrical activity in the brain.Summations of these electrical activities, (e.g., brainwaves), propagateto the surface and are detectable with electroencephalograms. Becausethe current flow in the human body is due to ion flow, a biopotentialelectrode is used, which forms an electrical double layer with the humanskin to sense the ion distribution.

EEG data can be classified in various bands. Brainwave frequenciesinclude delta, theta, alpha, beta and gamma frequency ranges. Deltawaves are classified as those less than about 4 Hertz (Hz) and areprominent during sleep. Theta waves have frequencies between about 3.5Hz to about 7.5 Hz and are associated with memories, attention,emotions, and sensations. Theta waves are typically prominent duringstates of internal focus. Alpha frequencies reside between about 7.5 Hzand about 13 Hz and typically peak around 10 Hz. Alpha waves areprominent during states of relaxation. Beta waves have a frequency rangebetween about 14 Hz and about 30 Hz. Beta waves are prominent duringstates of motor control, long range synchronization between areas,analytical problem solving, judgment, and decision making. Gamma wavesoccur between about 30 Hz and about 100 Hz and are involved in bindingof different populations of neurons together into a network for thepurpose of carrying out a certain cognitive or motor function, as wellas in attention and memory. Because the skull and dermal layersattenuate waves in this frequency range, brain waves above about 75 Hz(e.g., high gamma band or kappa band) are less easily measured thanwaves in lower frequency bands. EEG data may be used to determine anemotional or mental state of a person including, for example, attention,emotional engagement, memory or resonance, etc.

EEG signals may be measured using a plurality of electrodes placed on ascalp of a person (e.g., a user, a viewer, a subject, a panelist, aparticipant or a patient) to measure voltage fluctuations resulting fromelectrical activity associated with post synaptic currents occurring inthe milliseconds range within neurons of a brain. Though subcranial EEGcan measure electrical activity with high accuracy, surface electrodessuch as, for example, dry electrodes also provide useful neuro-responseinformation.

Many traditional EEG electrodes suffer from high impedance and/orrequire messy gels to increase signal quality. In addition, many knownEEG headsets utilize a helmet or head-strap type assembly that include alimited number of electrodes. These known headsets are uncomfortable towear and typically cannot effectively accommodate a variety ofdifferently sized heads.

To enable the surface EEG electrodes to effectively receive signals fromthe brain, the electrodes are to be placed as close to the scalp aspossible. The electrodes may be manually placed upon a subject's head ormay be contained in a wearable apparatus such as, for example, aheadset. However, a subject's hair may interfere with the contactbetween an electrode and the scalp by limiting the surface area contactof the electrode. For example the average person tends to have fromabout 80 to about 200 hair follicles per square centimeter(follicles/cm²). The hair strands and the hair follicles that areinterposed between the electrode and the scalp raise impedance severalmega-Ohms (MΩ). EEG systems with impedances greater than 100 kilo-Ohms(kΩ) are vulnerable to various sources of noise that obscure the readingof the EEG signal. Impedance can be reduced by applying pressure to theelectrodes thus decreasing the distance between the electrodes and thetissue of the scalp. However, too much pressure such as, for example,greater than two Newtons per millimeter square (N/mm²) results indiscomfort for the subject. In some examples, the pressure slightlycompresses the underlying stratum corneum, which is the outermost layerof the epidermis, for example the outermost 10-40 micrometers (μm).Known EEG sensors do not account for the thickness of one or morestrands of hair or hair follicles and do not effectively adjust to aspecific size of a user head and, thus, known systems cannot apply aneffective amount of pressure against the scalp. In some examplesdisclosed herein, a profile of the electrode including the electrode tipis designed to achieve both comfort and noise reduction. In addition, inexamples disclosed herein, a headset into which the electrodes areincorporated is modularly adjustable also to enhance comfort and noisereduction, as disclosed in greater detail below.

Because of the very low signal amplitude of EEG data and highimpedances, noise is a significant factor to consider in high qualityEEG instruments. Noise types are classifiable by the various sources ofthe noise such as, for example, skin potential noise, thermal noise,amplifier noise, electrode noise and interference noise.

Skin potential noise relates to stretching of the skin that causes achange of the potential at the electrode. Examples disclosed hereinmitigate skin potential noise by utilizing special electrode shape(s)such that the pressure imparted by the electrodes onto the scalp reducesskin potential noise. Because the skin is stretched and pressed by theexample electrodes described herein, there is less noise in general andless noise when the subject moves. An optimized pressure imparted by theelectrodes onto the scalp decreases skin potential noise whileincreasing comfort. An example pressure is less than about 2 N/mm².

Thermal noise is electronic noise generated by thermal agitation ofcharge carrying electronic components. Thermal noise is proportional tothe impedance and bandwidth and may be represented by the equation:V_(TH)=(4kTBR)^(1/2), where k is the Boltzman constant, T is temperaturein Kelvins (K), B is the bandwidth in Hertz, and R is the electrodeimpedance in Ohms (Ω). For example, with a target impedance of 1MΩ atroom temperature (T=300K) and 150 Hz bandwidth, the thermal noise willbe about 1 micro-volt root-mean-square (μVrms). Averaging over a numberindependently digitized electrodes, n, improves the signal-to-noiseratio by about 1/(n)^(1/2)(e.g., see FIG. 12B). As disclosed in greaterdetail below, an electrode shape with an effective diameter below 0.2millimeter (mm) allows up to about 100 independent digitized electrodesin an area having a diameter of about less than 15 mm. In some exampleEEG systems, there is a spatial resolution at the surface of the scalpof a maximum of about 15 mm. The examples disclosed herein mitigatethermal noise by averaging readings over multiple electrodes such as,for example, averaging with n=100 electrodes by a factor of 10.

Amplifier noise is noise intrinsic to the amplification process.Amplifier noise is typically small such as, for example, around 0.5μVrms at a bandwidth of about 150 Hz. The examples disclosed hereinmitigate amplifier noise by averaging readings over multiple electrodes,thereby cancelling at least a portion of the noise out. Averaging over nnumber of independently digitized electrodes improves thesignal-to-noise ratio by about 1/(n)^(1/2) (e.g., see FIG. 12B, thustaking into account both thermal noise and amplifier noise). Also, asdescribed above, with the example electrode shape disclosed below, whichhas an effective diameter below 0.2 mm, with more than 100 independentdigitized electrodes in an area having a diameter of less than about 15mm, and with a spatial resolution at the surface of the scalp of maximumabout 15 mm, the examples disclosed herein also mitigate amplifier noiseby averaging readings over multiple electrodes such as, for example, byaveraging with n=100 electrodes by a factor of 10.

Interference noise exists due to the presence of externalelectromagnetic fields (e.g. power lines). Electromagnetic induced noisecan penetrate the EEG signal over several pathways. For example, anelectric field can induce displacement current into the electrode leads,the electrode-skin interface or individual components of the EEG device(e.g. amplifier, power supplies, etc). Another source of electromagneticnoise is the common mode voltage on the subject's body (V_(c)), which iscomposed of a static voltage component (V_(s)) and a power-line-inducedcomponent (V_(a)). The power-line-induced component (V_(a)) is caused bya displacement current (I_(d)), which flows through stray capacitance(C_(d)). The size of this capacitance is determined by the proximity ofthe subject is to power sources. The power-line-induced component(V_(a)) can be as large as 20V, for example, if the subject grasps aninsulated power cord. Friction creates a charge that is stored incapacitance between the body and ground (C_(b)). For example, a thirdperson who is charged in this way can induce a static voltage into thesubject if he/she moves close to the subject. The examples disclosedherein enable the encapsulation of the EEG signal from externalelectromagnetic fields, which enhances the robustness of the EEG signalagainst electromagnetic noise sources. In some disclosed examples, afaraday cage is established around the EEG system to decouple the EEGsystem from environmental noise. Also, a dedicated shielding electrodewith low impedance connection (Z_(sh)<100 kΩ) to the subject's bodyensures that no displacement current penetrates the system.

Example headset devices and accompanying components for receivingneuro-response data from a user's head are disclosed herein. An exampleheadset disclosed herein is portable and comprises a plurality ofindependently adjustable bands operatively coupled to a first housingencasing a processor on one end and a second housing including anadjustment mechanism on the other end.

Example headsets described herein adapt to any head shape while alsoapplying adequate force to each of a plurality of electrodes (e.g., dryelectrodes) that are coupled to the headset to provide excellent EEGreadings. Some such example headsets provide a simple, cost effectiveand reliable solution for the use of a large number of dry electrodes.Some such example headsets ensure comfort, good electrode contact,through the hair operation, and shielding against line noise and othertype(s) of noise. Examples disclosed herein also include independentlyadjustable components to enhance comfort and wearability. In addition,examples disclosed herein greatly increase the number of channels (e.g.,electrodes) capable of gathering signals from the head, which asdetailed below, enhances data gathering and analysis.

An example device is disclosed herein that includes a first elongatedband coupled to a first housing to be located near a first ear of asubject and a second housing to be located near a second ear of thesubject, the first elongated band comprising a first set of electrodes.The example device also includes a second elongated band coupled to thefirst housing and to the second housing, the second elongated bandcomprising a second set of electrodes. In addition, the device includesa third elongated band coupled to the first housing and to the secondhousing, the third elongated band comprising a third set of electrodes,and a fourth elongated band coupled to the first housing and to thesecond housing, the fourth elongated band comprising a fourth set ofelectrodes. Other example devices include fewer or more adjustable bandsincluding, for example three, two, one, five, etc.

In some examples, each of the first, second, third and fourth elongatedbands is rotatably coupled to each of the first housing and the secondhousing. In some examples, each of the first, second, third and fourthelongated bands is removably coupled to each of the first housing andthe second housing.

In some examples, the first elongated band is to be located above anasion (e.g., the intersection of the frontal bone and two nasal bones)of the subject at about ten percent of a distance between the nasion andan inion (e.g., the projection of the occipital bone) of the subjectmeasured over a center of ahead of the subject, the second elongatedband is to be located above the nasion at about thirty percent of thedistance, the third elongated band is to be located at about halfwaybetween the nasion and the inion and the fourth elongated band is to belocated above the inion at about thirty percent of the distance.

In some examples, a sum of the number of electrodes in the first,second, third and fourth electrode sets comprises at least 2000electrodes. In some examples, the number of electrodes or channels couldbe 3000 electrodes or more. Also, in other examples, where less datachannels are needed or desired, there may be fewer electrodes.

In some examples, each of the first, second, third and fourth elongatedbands include an adjustable elastic band or strap to change a distancebetween the elongated band and a head of the subject.

In some examples, the device also includes one or more additionalelongated bands, each additional elongated band coupled to the firsthousing and the second housing and each additional elongated bandcomprising respective additional sets of electrodes.

In some examples, the device includes an adjustment mechanism coupled tothe first housing and/or the second housing to adjust a fit of thedevice on the subject.

In some examples, the first elongated band comprises a plurality ofextensions and the plurality of electrodes of the first set areindividually disposed at respective ends of the extensions. In someexamples, the extensions are flexible.

In some examples disclosed herein, the electrodes comprise at least aportion of a ring. In some examples, the electrodes comprise a ball. Insome examples, the electrodes comprise a hook. In some examples, theelectrodes comprise a pin.

In some examples, the electrodes are removably coupled to the respectivefirst, second, third or fourth elongated band.

In some examples, one or more of the electrodes is to compress a stratumcorneum of the subject at a force of about 1 N/mm² to about 2 N/mm².

In some examples, the disclosed device includes an analog-to-digitalconverter to convert signals gathered by the electrodes to digital data,an amplifier to amplify the signals, and a signal conditioner to removenoise from the signals. Some such example devices also include a dataprocessor to analyze the data in accordance with one or more analysisprotocols to determine a mental state of the subject and a transmitterto transmit at least one of the digital data or the mental state.

In some examples, the device is to be worn on a head of the subject.

Also disclosed herein are example methods that include obtainingelectroencephalographic data from a device comprising a first elongatedband coupled to a first housing to be located near a first ear of asubject and a second housing to be located near a second ear of thesubject, the first elongated band comprising a first set of electrodeshaving at least eight electrodes and a second elongated band coupled tothe first housing and to the second housing, the second elongated bandcomprising a second set of electrodes having at least eight electrodes.Some devices used in some such example methods include a third elongatedband coupled to the first housing and to the second housing, the thirdelongated band comprising a third set of electrodes having at leasteight electrodes and a fourth elongated band coupled to the firsthousing and to the second housing, the fourth elongated band comprisinga fourth set of electrodes having at least eight electrodes. Some suchexample methods further include analyzing the electroencephalographicdata to determine a mental state of the subject.

Some example methods include converting the electroencephalographic datagathered from the electrodes to digital data, amplifying theelectroencephalographic data and removing noise from theelectroencephalographic data. Other example methods include analyzingthe data in accordance with one or more analysis protocols to determinethe mental state of the viewer and/or transmitting at least one of thedigital data or the mental state.

Also disclosed herein is a tangible machine readable storage mediumcomprising instructions which, when read, cause a machine to at leastobtain electroencephalographic data from a device comprising a firstelongated band coupled to a first housing to be located near a first earof a subject and a second housing to be located near a second ear of thesubject, the first elongated band comprising a first set of electrodeshaving at least eight electrodes and a second elongated band coupled tothe first housing and to the second housing, the second elongated bandcomprising a second set of electrodes having at least eight electrodes.Some such example devices also include a third elongated band coupled tothe first housing and to the second housing, the third elongated bandcomprising a third set of electrodes having at least eight electrodesand a fourth elongated band coupled to the first housing and to thesecond housing, the fourth elongated band comprising a fourth set ofelectrodes having at least eight electrodes. Some example instructionscause a machine to analyze the electroencephalographic data to determinea mental state of the subject.

Some example instructions cause a machine to convert theelectroencephalographic data gathered from the electrodes to digitaldata, amplify the electroencephalographic data, and remove noise fromthe electroencephalographic data. Some instructions cause a machine toanalyze the data in accordance with one or more analysis protocols todetermine the mental state and transmit at least one of the digital dataor the mental state.

An example device disclosed herein includes a central body portion suchas, for example, a spine and a plurality of extensions extending fromthe central body portion, each extension having an end coupled to anelectrode. The example device also includes an adjustment band disposedalong a longitudinal axis of the central body to adjust a position ofthe extensions.

In some examples, the adjustment band is elastic. Also, in someexamples, the adjustment band has a circular cross section. In otherexamples, the adjustment band has a rectangular cross section. In someexamples, the adjustment band is slidably disposed along thelongitudinal axis.

In some examples disclosed herein, the central body portion comprises afirst protrusion, a second protrusion, and a recess formed between thefirst protrusion and the second protrusion, and the adjustment band isdisposed in the recess. In some examples, the central body portion andthe extensions comprises one or more of silicone or rubber. Also, insome disclosed examples, the device includes a flexible printed circuitboard encapsulated in the central body portion and extensions.

In some examples, each of the extensions is curved in a direction awayfrom the central body portion. In some such examples, each of theextensions is curved in the same direction. Furthermore, in someexamples, a first extension is located directly across the central bodyportion from a second extension. In some examples, the central bodyportion and the extensions are flexible but not elastic and theadjustment band is flexible and elastic.

In some examples, the electrodes are resilient (e.g., springy). Also, insome examples, the electrodes are removable. In some examples, theexample electrodes comprise at least a portion of a ring. The exampledevice also includes, in some examples, an array of electrodes disposedon one side of the central body portion. In some examples, the array isan embossed plate and the device includes up to 256 electrodes.

In some examples, a tightening of the adjustment band causes theelectrodes to apply a force to a head of a subject wearing the device.In some examples, the force is approximately the same at each electrode.

In some examples the disclosed device includes a silver nylon coating.

Some example devices disclosed herein include an analog-to-digitalconverter to convert a signal obtained from an electrode to a digitalsignal. Also, some example devices include a signal conditioner to atleast one of amplify a signal obtained from an electrode or remove noisefrom the signal.

In some examples, the device includes a cover partially surrounding anelectrode so that a first portion of the cover is disposed on a firstside of the electrode, a second portion of the cover is disposed on asecond side of the electrode, and an end of the electrode to contact atissue of a subject extends from the cover. In some examples, theelectrode has a cross section of less than about 0.5 mm, a first outerend of the first portion of the cover and a second outer end of thesecond portion of the cover are separated by a distance of about lessthan 1 mm, and the end of the electrode to contact the tissues extendsabout less than 0.2 mm from the cover.

Another example method disclosed herein includes obtainingelectroencephalographic data from a device worn by a subject, the devicecomprising a central body portion and a plurality of extensionsextending from the central body portion, each extension having an endcoupled to an electrode. The device of some such example methods alsoincludes an adjustment band disposed along a longitudinal axis of thecentral body to adjust a position of the extensions. Some such examplemethods also include analyzing the data to determine a mental state ofthe subject.

Some example methods also include one or more of converting a signalobtained from an electrode to a digital signal, amplifying a signalobtained from an electrode and/or removing noise from the signal.

Another example tangible machine readable storage medium disclosedherein includes instructions which, when read, cause a machine to atleast obtain electroencephalographic data from a device worn by asubject. The device of some such example instructions includes a centralbody portion, a plurality of extensions extending from the central bodyportion, each extension having an end coupled to an electrode and anadjustment band disposed along a longitudinal axis of the central bodyto adjust a position of the extensions. Some example instructionsfurther cause a machine to analyze the data to determine a mental stateof the subject.

Some example instructions further cause the machine to one or more ofconvert a signal obtained from an electrode to a digital signal, amplifya signal obtained from an electrode and/or remove noise from the signal.

Some example devices disclosed herein includes a first band comprising afirst set of electrodes and a second band comprising a second set ofelectrodes. In some examples, the first band and the second band are tobe oriented in a first direction to obtain first neuro-response datafrom a subject, and the first band and second band are to be oriented ina second direction to obtain second neuro-response data from thesubject, the second direction being substantially orthogonal to thefirst.

In some examples, the first band has a first end and a second end, thesecond band has a third end and a fourth end, the first end is coupledto the third end, and the second end is coupled to the fourth end. Also,in some examples, the first end is coupled to the third end through afirst housing and the second end is coupled to the fourth end through asecond housing. In some examples, the second housing includes aprocessor to analyze data collected from the electrodes. In addition, insome examples, the first housing includes an adjustment mechanism toadjust a fit of the device on the subject.

In some examples, the device is to be oriented in the second directionto gather a midline reading from a brain of the subject.

Other example methods disclosed herein include obtaining firstneuro-response data from a subject with a device oriented in a firstdirection. The device of some such example methods includes a first bandcomprising a first set of electrodes and a second band comprising asecond set of electrodes. The example methods also include obtainingsecond neuro-response data from the subject with the device oriented ina second direction, the second direction approximately orthogonal to thefirst.

Some examples methods also include analyzing the data gathered from theelectrodes using a processor disposed in a second housing. Also, someexamples methods include gathering a midline reading from a brain of thesubject with the device in the second direction.

Also disclosed herein is a tangible machine readable storage mediumcomprising instructions which, when read, cause a machine to at leastobtain first neuro-response data from a subject with a device orientedin a first direction, the device comprising a first band comprising afirst set of electrodes and a second band comprising a second set ofelectrodes. Some example instructions further cause the machine toobtain second neuro-response data from the subject with the deviceoriented in a second direction, the second direction orthogonal to thefirst.

Some example instructions further cause the machine to analyze the datagathered from the electrodes using a processor disposed in a secondhousing. Some example instructions further cause the machine to gather amidline reading from a brain of the subject with the device in thesecond direction.

Also disclosed herein are example devices that include a first set ofelectrodes to read an electrical signal from a tissue of a subject and asecond set of electrodes to read the electrical signal. In suchexamples, the first set and the second set of electrodes aremechanically coupled to a headset. In addition, in the example devices,the first set of electrodes comprises a first type of electrodes, andthe second set of electrodes comprises a second type of electrodes,different than the first type.

In some examples, the first type of electrodes comprises individuallymounted electrodes, and the second type of electrodes includes an arrayof electrodes. In some examples, two or more of the electrodes in thearray can be electrically shorted to form one electrode with anincreased surface area. Also, in some examples, the first type ofelectrode comprises at least one of a partial ring, a ball point and/ora hook. In addition, in some examples, the first set is disposed along afirst outer side of an elongated band and along a second outer side ofthe elongated band and the second set is disposed along a center axis ofthe elongated band.

Some example methods disclosed herein include reading an electricalsignal from a tissue of a subject using a first set of electrodes. Somesuch example methods also include reading the electrical signal using asecond set of electrodes, wherein the first set and the second set ofelectrodes are mechanically coupled to a headset and the first set ofelectrodes comprises a first type of electrodes and the second set ofelectrodes comprises a second type of electrodes, different than thefirst type.

Also disclosed herein is a tangible machine readable storage mediumcomprising instructions which, when read, cause the machine to at leastread an electrical signal from a tissue of a subject using a first setof electrodes and read the electrical signal using a second set ofelectrodes. The first set and the second set of electrodes used withsuch example instructions are mechanically coupled to a headset and thefirst set of electrodes comprises a first type of electrodes and thesecond set of electrodes comprises a second type of electrodes,different than the first type.

Some example devices disclosed herein include a first housing comprisinga magnetic lock. Some such example devices also include a firstelongated band having a first end adjustably coupled to the firsthousing. The first elongated band comprises a first plurality ofelectrodes. Some such example devices also include a first adjustablestrap. The first adjustable strap comprises a first magnetic fastener tomagnetically link with the magnetic lock at a first engagement point tosecure the first elongated band in a first position and to magneticallylink with the magnetic lock at a second engagement point to secure thefirst elongated band in a second position.

In some examples, the device is to be worn on a head of a subject,wherein the first position is closer to a top of the head than thesecond position and adjustment of the first magnetic fastener from thefirst position to the second position tightens the first elongated bandand brings the electrodes closer to the head. In some examples, thefirst elongated band is removably coupled to the first housing.

Some such example devices also include a second elongate band having asecond end adjustably coupled to the first housing. The second elongatedband comprises a second plurality of electrodes. Some such exampledevices also include a second adjustable strap. The second adjustablestrap comprises a second magnetic fastener to magnetically link with themagnetic lock at a third engagement point to secure the second elongatedband in a third position and to magnetically link with the magnetic lockat a fourth engagement point secure the second elongated band in afourth position.

In some examples, the first elongated band and second elongated band areindependently adjustable. Also, in some examples, the first elongatedband and the second elongated band are independently removable.

Other methods disclosed herein include releasing a first magneticfastener of an adjustable strap of a first elongated band of a devicefrom a first engagement point with a magnetic lock of a first housing tounlock the first elongated band from a first position. Some such examplemethods also include coupling the first magnetic fastener to themagnetic lock at a second engagement point to secure the first elongatedband in a second position.

Some examples methods include releasing a second magnetic fastener of anadjustable strap of a second elongated band of a device from a thirdengagement point with the magnetic lock to unlock the second elongatedband from a third position. Some example methods also include couplingthe second magnetic fastener to the magnetic lock at a fourth engagementpoint to secure the second elongated band in a fourth position.

Also, some example methods include one or more of independentlyadjusting the first elongated band and second elongated band and/orindependently removing the first elongated band and the second elongatedband.

Some example devices disclosed herein include a first hub and a firstremovable band comprising a first plurality of electrodes removablycoupled to the first hub. In some such examples, the first bandcomprises a first cover comprising at least one of nylon or silver. Thefirst band is washable in an automated washing machine. In someexamples, the cover is stretchable. In some examples, the deviceincludes a second removable, washable band comprising a second pluralityof electrodes. Also, in some examples, the first removable band isadjustably coupled to the first hub and usable for a first subjecthaving a first head size and a second subject having a second head size,the second head size different than the first head size.

Some example methods disclosed herein include removing a first removableband comprising a first plurality of electrodes from a first hub, thefirst band comprising a first cover comprising at least one of nylon orsilver. Some such example methods also include washing the first band inan automated washing machine. Also, some example methods includeremoving a second removable, washable band comprising a second pluralityof electrodes from the first hub and washing the second band in theautomated washing machine. In addition, some example methods includeadjusting the first removable band relative to the first hub to fit afirst subject having a first head size and/or readjusting the firstremovable band relative to the first hub to fit a second subject havinga second head size, the second head size different than the first headsize.

Turning now to the figures, FIGS. 1-4 show an example headset 100. Theexample headset may be used for instance, to gather medical informationfrom a patient in a medical or a home environment, to control aspects ofa game or other entertainment, to provide data as part of a fitnessregime, to collect audience measurement data, to control remote devicesand/or multiple other uses. The example headset 100 of FIG. 1 includes aplurality of independently adjustable bands, each band comprising aplurality of electrodes for receiving signals from a head of a user,subject, viewer and/or panelist. As used herein, a participant is aperson who agreed to be monitored. Typically, a participant providestheir demographic information (e.g., age, race, income, etc.) to amonitoring entity (e.g., The Nielsen Company) that collects and compilesdata about a topic of interest (e.g., media exposure). Morespecifically, the headset 100 of the illustrated example includes afirst band 102, a second band 104, a third band 106 and a fourth band108. Each of the bands 102-108 includes a plurality of electrodes. Inthe illustrated example, the electrodes are partially ring-shapedelectrodes. The ring-shaped electrodes may have, for example, a diameterof less than about 3 mm and a length less than about 3 mm. The biggerand wider the dimensions of an electrode, the more force needed tosufficiently apply the electrode to the scalp. In some examples, theelectrodes have a diameter of about 1 mm to about 2 mm. However, manyother types, sizes and/or shapes of electrodes may be additionally oralternatively used as discussed in further detail below. In the exampleof FIG. 1, the bands 102-108 are intended to extend over the head of auser from the left side of the head to the right side of the head. Eachof the bands 102-108 comprises an elongated structure with alongitudinal axis. In this example, each band 102-108 takes the form ofa spine-shaped structure 110, 112, 114 and 116, respectively. Each ofthe spines 110, 112, 114, 116 supports an elastic adjustment band orstrap 118, 120, 122 and 124, respectively. Each of the bands 102-108 isrotatably and removably coupled on one side to a first housing 126 androtatably and removably coupled on the other side to a second housing128. For example, the bands 102-108 may include a pivot type connectionand/or a snap fastener to plug the bands 102-108 into the headset. Inother examples, the bands are fixedly coupled to the headset. In theexample shown, the first housing 126 may be placed near the right ear ofa user and the second housing 128 may be placed near the left ear of theuser so that the bands 102-108 are disposed over the head of the userfor reading electrical activity along the scalp. The headset 100 of theillustrated example also includes an additional support band 130, whichis adjustable and may be, for example, elastic or any other suitablematerial that may be used for tightening and securing the headset 100around the back of the head of a user. In the example shown, the headset100 includes four bands. However, in other examples, the headset 100 mayinclude fewer or more (e.g., three or less or ten or more) adjustablebands. Each band may carry about eight to about 256 or more electrodesper band.

In the example of FIG. 1, the bands 102-108 are rotatably and removablycoupled to the first and second housings 126 and 128 to allow a user toadjust the position of the bands 102-108 over the head of the user. Thebands 102-108 of this example may be rotated toward the inion (theprojection of the occipital bone) or the nasion (the intersection of thefrontal bone and two nasal bones) of the user to position the electrodesin specific locations for measuring electrical activity. Each of thespines 110-116 of FIG. 1 is comprised of a flexible material such as,for example, plastic, rubber, polyurethane, silicone and/or any othersuitable material. The flexibility of the example spines 110-116 allowsthe headset 100 to sit comfortably on the head of a user. Further, theelastic straps 118-124 of the illustrated example are supported by thespines 110-116 and may be pulled to tighten the spines 110-116 downwardand, thus, to increase the pressure of the electrodes against the scalpof a user. In the illustrated example, the elastic straps 118-124 areflexible and elastic. In addition, the elastic straps 118-124 of FIG. 1are slidably and translatably coupled to the spines 110-116. Further, inthe example of FIG. 1 the entire headset 100 and/or the individual bands102-108 may be cleaned in a typical washing machine for routine cleaningand/or to disinfect and sterilize the headset 100 such as, for example,between uses or between users. In some examples there are varioustemplates of headsets for differently sized heads. People have differenthead sizes based on age, sex, race and/or genetics. For example, humanheads may range from about 54 cm to about 65 cm in circumference. Insome examples there may be two or three template headsets. For example,a first template may accommodate heads of about 56 cm in circumference,a second template for heads of about 59 cm in circumference and a thirdtemplate for heads of about 62 cm in circumference. In these examples,the center band (e.g., along the midline) may be about 23 cm, about 25cm and about 26 cm, respectively. Thus, in some examples, the templatesmay include bands of multiple sizes that differ in length from about 1cm to about 2 cm between different templates. The different templatesizes are used as a coarse adjustment when fitting a headset on asubject. The adjustment of the elongated bands is then used to perfectthe fit as a fine adjustment, which is detailed more below.

In the example shown, the first housing 126 includes an exampleadjustment mechanism 132 (shown in FIG. 10) to adjust the length of theelastic straps 118-124. The elastic straps 118-124 of the illustratedexample may be pulled tight via the adjustment mechanism 132 to positionthe respective bands 102-108 and tighten the spines 110-116 downwardtoward the scalp. An example adjustment approach is disclosed in greaterdetail below in connection with FIG. 10.

In the example shown, the second housing 128 supports electricalcomponents 134 such as, for example, a processor for processing thesignals from the electrodes, disclosed in further detail below. In someexamples, the processing occurs at the headset as an all-in-one orself-contained system. In other examples, some of the processing occursat the headset and some processing occurs remotely after the headsettransmits data or semi-processed results to a remote site such as, forexample, via a wireless connection. In still other examples, all data isstreamed to a remote analyzer for processing. The electrical components134 of the illustrated example are used to, for example, convert theelectroencephalographic data from analog data to digital data, amplifythe electroencephalographic data, remove noise from the data, analyzethe data, and transmit the data to a computer or other network. Thesecond housing 128 of the illustrated example includes hardware andsoftware such as, for example, an amplifier, a signal conditioner, adata processor and/or a transmitter for transmitting signals to a datacenter or a computer. Each of the spines 110-116 of the illustratedexample are communicatively coupled to the electrical componentsincluding the example processor via a wired connection and/orwirelessly. In other examples the electrical components 134 aresupported in the first housing 126 and the adjustment mechanism 132 issupported on or in the second housing 128.

FIG. 4A illustrates a perspective view of the headset 100 worn on thehead of a user. As shown, the bans 102-108 traverse over the head from aleft side to a right side. The location of the bands 102-108 may beadjusted and the elastic straps 118-124 may be tightened to tighten thebands 102-108 downward on the user's head. In the example shown, theadditional support band 130 is stretched around the back of the head andmay be pulled tight or adjusted to secure the headset 100 to the head ofthe user.

As shown in FIG. 4B, in addition to being worn in the side-to-sideorientation explained above, the headset 100 of the illustrated examplemay be worn in a front to back orientation, wherein the first housing126 or the second housing 128 is placed over the forehead of a user andthe bands 102-108 traverse to the other of the second housing 128 or thefirst housing 126, which is disposed on the back of the user's head. Thebands 102-108 may be laterally adjusted and/or tightened individuallyfor optimum reading. The orientation of FIG. 4 facilitates a midlinereading of by the headset 100.

FIG. 5 illustrates the example band 102 that may be used with theheadset 100. As seen, the first band 102 is comprised of the first spine110 and the first elastic strap 118. The first spine 110 is designed ina spine-like structure having a plurality of opposed extensions, 136a-136 t, similar to that of a spine and vertebrae arrangement. Each ofthe extensions 136 a-136 t is coupled to a partially ring-shapedelectrode 138 a-138 t, respectively. The extensions 136 a-136 t areflexible to retract and bend as the first band 102 is tightened downover the head of a user. In the example shown in FIG. 5, the electrodes138 a-138 t are molded within the extensions 136 a-136 t of the firstspine 110. However, in other examples, the electrodes 138 a-138 t may beremovably coupled (e.g., snapped on) to the extensions 136 a-136 t. Eachof the electrodes 138 a-138 t has its own channel running through thespine 110. Also, in some examples, the readings from multiple electrodesmay be averaged together to increase the effective surface area betweenthe electrodes and the scalp and decrease impedance, as disclosed inmore detail below. The first spine 110 further includes a housing 140that may contain individual amplifiers and analog-to-digital convertersfor each of the electrode channels. The spine 110 also includes a wire142 to communicatively couple the electrodes 138 a-138 t to theprocessor 134 and/or to the other electrical components of the secondhousing 128 for processing. In other examples the spine 110 includes awireless transmitter and power supply, for example in the housing 140,for wirelessly transmitting data to the processor 134 in the secondhousing 128 or to another processor outside of the headset 100.

The topside of the first spine 110 includes a plurality of runners 144a-144 j, which are extensions or protrusions for guiding and securingthe first elastic strap 118 along the topside of the first spine 110. Inthe illustrated example, the runners 144 a-144 j are formed in pairs oftwo elongated runners extending along opposite sides of the elasticstrap 118. In other examples, the runners 144 a-144 j are implemented byone or more elongated circular tubes running over the elastic strap 118.The first spine 110 further includes a first eye 146 and a second eye148. In the example shown the second eye 148 is coupled to the housing140. The first elastic strap 118 is disposed between the runners 144a-144 j along the longitudinal axis on top side of the first spine 110and also through the first and second eyes 146, 148. The first andsecond eyes 146, 148 assist in maintaining the position of the elasticstrap 118 on the spine 110. The first elastic strap 118 is slidablyengaged along the top side of the first spine 110 to slide as the firstelastic strap 118 is stretched and pulled tight or released. In theexample shown in FIG. 5, the first elastic strap 118 has a circularcross-section. However, in other examples, the first elastic strap 118has a rectangular, elliptical, or any other cross-section shape. In someexamples, the elastic strap 118 is shaped to enhance shielding of theelectronic signals propagating through the spine 110.

In the example shown in FIG. 5, the first band 102 includes 20electrodes on the first spine 110. However, in other examples, the firstspine 110 may carry other numbers of electrodes (e.g., 256 or moreindividual electrodes).

FIG. 6 is an enlarged view of a portion of the first band 102. As seenin FIG. 6, the extensions 136 a-136 c and 136 k-136 m are curvedslightly downward, which positions the electrodes 138 a-138 c and 138k-138 m downward toward the scalp. As shown in FIG. 6, the first elasticstrap 118 is disposed along the top of the first spine 110 and held inplace by the runners 144 a-144 c and the first eye 146. Each of theextensions 136 a-136 c and 136 k-136 m is coupled to a respective one ofthe electrodes 138 a-138 c and 138 k-138 m. As the first elastic strap118 is pulled tighter, the elastic strap 118 is effectively shortened,thereby creating a downward force on the extensions 136 a-136 c and 136k-136 m, which flex upward or bow outward to force the electrodesagainst the scalp of a user. The example bands 102-108 are designed tocreate a force of about 1 N/mm² to about 2 N/mm² on the scalp of a user.In some examples, the applied force is the same for each electrode.

FIG. 7 is a cross-sectional view of the first band 102 having the firstspine 110 and the first elastic band 118. The extensions 136 a and 136 kare curved downward. The electrodes 138 a and 138 k are partiallyring-shaped electrodes coupled to the underside of the extensions 136 aand 136 k, respectively. The ends of the electrodes 138 a and 138 k aremolded within the first spine body 110 and operatively coupled to aprinted circuit board (PCB) 150, which runs through the first spine 110.Each of the electrodes 138 a-138 t (shown in FIG. 5) is communicativelycoupled to the PCB 150. The PCB 150 of the illustrated example includesthree electronics layers (e.g., layers including at least one electricalcomponent or circuit line) and one shielding layer.

Several example methods of shielding are disclosed herein to reduce oreliminate electromagnetic interference with EEG readings including, forexample, the reduction of impedance to reduce and/or eliminate the needfor external shielding in some instances. The examples disclosed hereinenable high-resolution EEG measurement with high impedanceskin-electrode interfaces and inter-electrode high impedance mismatches.In some examples, the high-resolution measurement is achieved by batterypowered EEG measurement devices such as, for example, the headsetsdisclosed herein, that may include floating driven low-impedance ground,wireless communication and the example disclosed shielding techniques.FIGS. 8A, 8B and 8C illustrate the effect of impedance through exampleelectrical circuit representations of an EEG system without externalnoise sources (FIG. 8A), a wet electrode EEG system with external noisesources (FIG. 8B), and a dry electrode EEG system with external noisesources (FIG. 8C), which represents the example systems disclosedherein.

FIG. 8A illustrates an example EEG system 800 in which a subject 802 iscoupled to an EEG measurement device 804 such as, for example, theheadsets disclosed herein. In this example, the headset 804 is awireless EEG measurement device. The potential between a driven groundelectrode 806 and a data electrode 808 is measured by applyingbio-potential electrodes on the head of the subject 802. FIG. 8Arepresents an ideal or theoretical situation in which there is noexternal noise such as, for example, a completely shielded room in whichthe subject never moves. In such a system, measurements between the dataelectrode 808 and the ground electrode 806 are indicative of the signalof from the EEG source (e.g., the subject's brain) without noiseartifacts.

In a real world environment (FIGS. 8B and 8C), there are external noisesfrom electromagnetic (e.g., power lines) or electrostatic (e.g.,walking) sources. Because of the low signal amplitudes of EEG data (forexample, about 1 μV to about 100 μV) and high electrode-skin impedances(for example, greater than about 100 kΩ), external noise sources play asignificant role in the quality of the EEG data. Electromagnetic inducednoise can penetrate the EEG signal over several pathways. For example,an electric field can induce displacement current 820 (I_(EM2H),electromagnetic source to headset) that flows through the associatedcapacitance 822 (C_(EM2H), electromagnetic source to headset), into theelectrode leads of the headset 804, the electrode-skin interface orindividual components of the EEG device (e.g. amplifier, power supplies,etc.). Another source of electromagnetic noise is the common modevoltage on the subject's body. A displacement current 824 (I_(EM2S),electromagnetic source to subject), flows through stray capacitance 826(C_(EM2S), electromagnetic source to subject). Stray capacitance is thecapacitance between any two adjacent conductors. The size of thiscapacitance is determined by how close the subject is to power sources.The noise attributable to the stray capacitance can be as large as, forexample if the subject grasps an insulated power cord, 20V.

Another source of noise is electrostatic. Friction creates charge thatis stored in the capacitance 828 (C_(ES2S), electrostatic source tosubject) between the body and ground. For example, a third person who iselectrostatically charged can induce a static voltage and associatedcurrent 830 (I_(ES2S), electrostatic source to subject), into thesubject if he/she moves close to the subject. Displacement current 832(I_(ES2H), electrostatic source to headset), is also injected andcapacitance 834 (C_(ES2H), electrostatic source to headset), is alsoinduced from the external electrostatic noise to the headset 804.

The external noise capacitively injects displacement current820(I_(EM2H)), 832 (I_(ES2H)) in the subject 802 or the headset 804,which will be converted by the impedances of the data electrodes (Z_(E))and ground electrode (Z_(G)) into additional noise that can bemagnitudes higher than the signal of interest. If there are equalimpedances, the noises will cancel out. In a low impedance wet system(FIG. 8B), the conversion of displacement current into additional noiseis minimized such that noise can be kept under acceptable values.Typically, however, it is not achievable for the impedances of the dataelectrodes (Z_(E)) and ground electrode (Z_(G)) to be equal.

In a system including dry electrodes with high impedance electrode-skininterfaces (e.g., greater than about 100 kΩ) (FIG. 8C), the impedancefrom the data electrode (Z_(E)) is much greater than the impedance fromthe ground electrode (Z_(G)). In this configuration, the displacementcurrents 820(I_(EM2H)), 832 (I_(ES2H)) would typically flood the systemwith noise. However, the examples disclosed herein couple a conductivematerial that has an electrode-skin impedance of less than about 100 kΩto the body of the subject 802. Example conductive materials include analuminum sheet and/or a silver coated nylon. The conductive material andthe subject 802 form a shield 840 such that the EEG device (e.g.,headset 804) is capacitively decoupled from the environment. The shield840 is coupled to the subject via a shield electrode 842 that has a lowimpedance (Zs). The shield 840 and shield electrode 848 effectivelyencapsulate the headset 804. The displacement currents 820(I_(EM2H)),832 (I_(ES2H)) that result from external noise sources such aselectromagnetic sources (e.g., power lines) or electrostatic noisesources (e.g., such as walking of the subject or near other people)flows through the path of least resistance (e.g., through the shieldelectrode with low impedance Zs) and, thus, these displacement currents820(I_(EM2H)), 832 (I_(ES2H)) are not visible at the input of the EEGmeasurement devices (e.g., headset 804).

In some examples disclosed herein, a low-impedance electrode-skininterface for ground and shield electrodes is realized by introducing anunconventional location for the ground electrode. For example, FIG. 9 isa schematic view of a top of head showing example electrode and groundplacement using the example headset of FIG. 1 or other example headsetsdisclosed herein. There are several abbreviations in the diagramincluding “N” for nasion, “F” for frontal (e.g., in relation to thefrontal lobe of a brain, which is the area located at the front of eachcerebral hemisphere), “A” for ear lobe, “C” for center (e.g., inrelation to a center area of the brain), “T” for temporal (e.g., inrelation to the temporal lobe of the brain, which is located inferiorand posterior to the frontal lobe at each cerebral hemisphere), “P” forparietal (e.g., in relation to the parietal lobe of the brain, which islocated posterior to the frontal lobe), “O” for occipital (e.g., inrelation to the occipital lobe of the brain, which is located at theback of the head), “I” for inion, and the subscript “z” for readingstaken along the midline of the brain.

As shown in FIG. 9, a driven ground electrode 151, which in this exampleis a low impedance dry electrode, and an electrode for the shield areplaced at the forehead. A second data electrode 153 is placed at atypical ground location such as, for example, an earlobe or a mastoid.The forehead is an unconventional location for the ground electrode 151because of the underlying muscle movement. Ear lobes and mastoids arerelatively quiet areas (e.g., relatively free from of electrodeactivity) of the scalp that are free of hair, which lowers the impedanceat these positions, have low brainwave activity and are less susceptibleto artifacts from muscle movement such as, for example, movement of thejaw muscles. Subtracting this additional added data channel 153 fromevery other data channel (in either the digital domain or the analogdomain) will cancel the unwanted effect of the ground electrode at theforehead. This is referred to as referencing, where the “0” potential ofthe system has to be shifted (or referenced). The equation in FIG. 9shows that the effect of the ground electrode 151 at the forehead dropsout when the data electrode 153 is subtracted from a data channel (e.g.,data channel FC5). Thus, a low impedance electrode-skin connection(e.g., less than about 100 kΩ) is achieved without the use of gel at theforehead of a subject.

In addition to enabling the system to have a dry low-impedanceinterface, these examples also enhance the common mode rejection ratio(CMRR) because common signals (noise) will be attenuated by thesubtraction. CMRR is where devices tend to reject input signals commonto two input leads. A high CMRR is desired in applications where thesignal of interest is a small voltage superimposed on potentially largevoltage offset.

Examples disclosed herein obtain EEG readings of high quality with lownoise for several reasons. Some such examples are self-contained unitsand, therefore, the EEG platform of these examples is electricallydisconnected or decoupled from external electric sources. Additionallyor alternatively, examples disclosed herein include a conductive layerthat is coupled to the human body (e.g., the shield of FIG. 8C) andencases the EEG platform (e.g., the headset 804 of FIG. 8C). Having alow impedance coupling between the conductive layer and the human bodyand a high impedance to the EEG platform also capacitively disconnectsthe EEG platform from the environment such that external sources cannotpenetrate the EEG platform and capacitive coupled displacement currentsare not detectable or visible at the input of the EEG platform, asdisclosed above. Thus, the EEG platform is electrically isolated fromexternal noise sources. Examples disclosed herein provide lowelectrode-skin impedance such as, for example, as low as about 100 kΩ.

In other examples, additional shielding is provided. In some suchexamples, each electrode includes an individual shield, the cables areshielded, and/or all electronics include further shields. In someexamples, the headset includes a conductive paint to enhance shielding.Also, in some examples, the headset includes a cover such as, forexample, a silver-coated nylon, which also enhanced shielding.

Furthermore, as disclosed herein, some example systems utilize reducedshielding or no shielding because the electrodes gather data with suchlow impedance that the signal-to-noise ratio is high enough to enablethe data to be processed without additional shielding. Also with suchlow impedance, noise sources become less relevant. The low capacitanceof the components in some example systems reduces the need foradditional shielding and, thereby reduces the complexity of the system.Low impedance and low capacitance may be achieved, for example, withminiature signal lines in the flexible circuit board 150 and via the useof small profile electrodes that are kept close to the head as disclosedherein.

FIG. 10 is an enlarged view of the example adjustment mechanism 132,which can be incorporated into the first or second housing 126, 128. Theadjustment mechanism 132 of the illustrated example comprises a magneticblock or lock 152. Each of the elastic straps 118-124 is coupled to anattachment strip 154-160, respectively. Each of the attachment strips154-160 comprise a plurality of vertically arranged magnetic elements,162 a-162 f, 164 a-164 f, 166 a-166 f and 168 a-168 f, respectively.Each of the attachment strips 154-160 is magnetically releasable andlockable with the magnetic lock 152 at a plurality of positions. In theillustrated example, there are multiple positions for coupling each oneof the attachment strips 154-160 to the magnetic lock 152. The magneticelements 162 a-162 f, 164 a-164 f, 166 a-166 f, and 168 a-168 f on theattachment strips 154-160 allow a user to adjust the length of theelastic straps 118-124. For example, if a user wants to tighten the band102 for comfort and/or signal connection, the user releases thecorresponding attachment strip 154 from engagement with the magneticlock 152, pulls the attachment strip 154 in a downward direction toanother magnetic element 162 a-162 f, which pulls the elastic strap 118and causes the spine 110 of the band 102 to move in a direction closerto the user's head causing the respective electrodes to more closelyengage the user's scalp. The user then engages the magnetic strip 154with the magnetic lock 152 to lock the band 102 in the desired position.If the user wants to loosen the band 102 for comfort, to adjust theelectrode placement and/or signal connection, and/or to remove theheadset 100, the user may release the attachment strip 154 from themagnetic lock 152 and moves the attachment strip 154 in an upwarddirection to loosen the elastic strap 118 and to cause the spine 110 ofthe band 102 to move in a direction away from the user's head therebycausing the respective electrodes to more lightly engage or to disengagethe user's scalp. The user then reengages the attachment strip 154 withthe magnetic lock 152 to lock the band 102 in a desired position. Thesame process may be repeated with any other band. To fully remove aband, the corresponding magnetic strip is removed from the attachmentlock 152 and not reengaged. Also, in some examples, there may bemagnetic balls or endpoints to each elastic strip that engage one of aplurality of magnetic locks supported on the adjustment mechanism 132.In such examples, the bands are adjustable into multiple positionsdefined by the position of the magnetic locks. In other examples, theelastic bands on the spine may be adjusted in any other fashion.

FIGS. 11A, 11B, 11C and 11D illustrate example electrodes that may beused with the bands 102-108 of the headset 100. Sensor (electrode)geometries and materials affect the impedance characteristics of thesignal connections. In some examples the electrodes are formed, forexample, of silver or silver chloride, which may provide, for exampleabout 10 MΩ of impedance per square millimeter of contact surface. Othermaterials with other impedance per area values may additionally oralternatively be used.

The example ring-shaped electrode 138 a shown in FIG. 11A comprises asmooth curved element. In the example of FIG. 11A, the ends of thering-shaped electrode 138 a are molded into the body of the spine 110.However, in other examples, the electrodes are removably coupled to thebody of the spine 110. The electrode 138 a of the illustrated examplemay be constructed of any electrically conductive element. Theelectrodes in the illustrated example are less than about 3 mm indiameter and greater than about 3 mm in length. This configurationallows the electrode to penetrate the hair of a user and make contactwith the scalp. The ring-shaped electrode 138 a of the illustratedexample is sufficiently resilient (e.g., springy) to flex and adjustwhen pressure is applied downward toward the head.

The example shown in FIG. 11B is a hook-shaped electrode 170. Similar tothe example ring-shaped electrode 138 a of FIG. 10, the examplehook-shaped electrode 170 of FIG. 11B is curved, thereby allowing theelectrode to penetrate the hair and lay against the scalp of a user.FIG. 11C illustrates an example ball electrode 172. The example ballelectrode 172 of FIG. 11C comprises a shaft 174 and a ball 176. The ball176 of the illustrated example can easily penetrate the hair and touchthe scalp of a user. In some examples, the ball electrode has animpedance of about 1.3MΩ, the ball had a diameter of about 1.8 mm, and,when pressed into the tissue, the ball has an effective contact area ofabout 7.7 mm². Increasing the size of the electrodes increases thecontact area and further decreases impedance. For example, if a ballelectrode with four times the diameter of the example ball electrodedescribed above is used, the contact area will be about 30 mm², and theimpedance will be reduced to about 300 kΩ.

FIG. 11D is an example implementation of the first spine 110 equippedwith a central array plate 178. In this example, there is one arrayplate 178. However, in other examples, there may be a plurality of arrayplates. The bottom side of the first spine 110 of the illustratedexample includes the central array plate 178 to increase the amount ofelectrodes touching the scalp. The central array plate 178 of theillustrated example is embossed to include a plurality of pin-likeindividual electrodes. As the first elastic strap 118 (shown in FIG. 1)is tightened, reflective pressure from the scalp forces the extensions136 a-136 t (shown in FIG. 5) of the first spine 110 to flex outward sothe bottom of the first spine 110 is moved closer to the scalp. As thebottom of the first spine 110 approaches the scalp, some or all of theindividual electrodes on the central array plate 178 penetrate the hairand touch the scalp of the user. In the example shown in FIG. 11D, thecentral array plate contains approximately 256 individual electrodes ormore. Each electrode has its own channel that is communicatively coupledto the processor via the PCB 150. With the large number of electrodesincluded on the example array plate 178, the number electrodes disposedat the extension on the spines, and the number of spines included in aheadset 100, the example headset 100 gathers signals from a very largenumber of channels. If, for example, the headset 100 includes tenspines, the number of channels could easily surpass 2000 or 3000channels. This large number advantageously provides a larger amount ofdata from multiple areas of the brain to create a clearer and morecomprehensive picture of brain activity. This large amount of channelsalso provides an oversampling, which enables virtual movement of anelectrode as disclosed below.

In some examples, the array plate 178 enables the headset 100 to includeabout twenty-four electrodes within about a 1.5 cm radius. Theelectrodes within the same area likely collect the same signal orsubstantially similar signals. In some examples, the quality of thesignals collected through the electrodes can be improved by effectivelyincreasing the surface area of the electrode contact with the scalp bycombining two or more electrodes and/or by averaging two or more of thesignals collected via the electrodes within the radius for use as asingle value.

In some examples, individual electrodes may be coupled in a parallelconnection to effectively increase the contact area of the electrodes bythe number of electrodes coupled in parallel. Because of the parallelconnection, if one electrode has a high impedance or otherwise gathers apoor signal, the effect of that electrode is small on the whole parallelconfiguration. The coupling of electrodes reduces the impedance and theeffect of thermal noise. In some examples, the electrodes are fixedlycoupled in parallel. In other examples, two or more electrodes arecoupled via a switching circuit, which can be selectively activated toshort out one or more electrodes to effectively increase the surfacearea contact between the electrodes and the tissue on the scalp. Byshorting out one electrode and increasing the effective surface area ofa second electrode, the impedance is lowered, which also enables thesecond electrode to effectively read higher frequency bands.

An example switching circuit 300 is shown in FIG. 12A. The examplecircuit 300 includes a plurality of electrodes, Electrode A 302,Electrode B 304, Electrode C 306 and Electrode D 308. In other examplesthere may be other numbers of electrodes including, for example, two,five, ten, fifty, etc. These electrodes 302, 304, 306, 308 may representa subset of the plurality of electrodes disposed within a small areasuch as, for example, the area defined above with about a 1.5 cm radius.In the example, each electrode 302, 304, 306, 308 is coupled to arespective analog-to-digital converter 310, 312, 314, 316. In otherexamples, the electrodes 302, 304, 306, 308 may be coupled to the sameanalog-to-digital converter or a different number of analog-to-digitalconverters. In addition, in some examples, the electrodes 302, 304, 306,308 may additionally or alternatively be coupled to other signalprocessing components such as, for example, the components disclosedbelow with FIGS. 36 and 37.

In addition, as shown in FIG. 12A, multiple electrodes such as, forexample, adjacent electrodes may be coupled via switches. For example,Electrode A 302 and Electrode B 304 may be selectively electricallycoupled via a first switch 318. Electrode B 304 and Electrode C 306 maybe selectively electrically coupled via a second switch 320. Also,Electrode C 306 and Electrode D 304 may be selectively electricallycoupled via a third switch 322. In other examples, additional and/oralternative electrode(s) may be coupled via the switches 318, 320, 322and/or additional switch(es). In some examples, one or more of theswitches includes a transistor. Also, in some examples, a controllercontrols each switch (e.g., controller 2 324 controls switch 322). Insome examples, a single controller controls multiple switches (e.g.,controller 1 326 controls switches 318, 320). The switches 318, 320, 322can be opened to electrically decouple the associated electrodes, or theswitches 318, 320, 322 can be closed to electrically couple associatedelectrodes. Electrically coupling two electrodes is a shorting out thatincreases the contact area of the shorted out electrode, which as notedabove, decreases impedance and increases signal quality.

As noted above, another method to increase signal quality includesaveraging signals from two or more channels (e.g., electrodes). Theaveraging will increase the signal-to-noise ratio by reducing boththermal noise and amplifier noise. An example graphical representationof signal averaging is shown in FIG. 12B. As shown, there are fourchannels (C1, C2, C3, C4) of signals represented on the logarithmicscale. The signal from each channel includes the EEG signal plus thebackground noise. The first peak, at 10 Hz, shows the subject closinghis eyes. Thus, electrostatic noise from the contractions of thesubject's muscles is increased. Another increase is background noise isthe second peak, at 50 Hz, which is electromagnetic noise due to powerlines (e.g., power line frequency in Europe). As shown in FIG. 12B, theaverage of the four channels, which is shown as the darkest line has thelowest values on the y-axis and, thus, carries the lowest amount ofnoise. As the frequency level increases, the noise reduction in theaveraged signal increases such that the average is more purified fromnoise than any of the individual component signals. This disparity growsas frequency increases. Thus, averaging signals enables higherfrequencies to be read including, for example frequencies as high asabout 100 Hz or even about 120 Hz, with less noise interference.

A combination or hybrid system may also be used that combines thecoupled electrodes and the averaged signals. For example, a set ofelectrodes within a specific area may include subsets of electrodes thatare electrically coupled via fixed parallel couplings or via selectiveswitching. Each subset may provide a high quality signal. Signals fromtwo or more subsets may be averaged to further increase signal quality.

Furthermore, due to a large number of electrodes, a user or an automatedanalyzer could determine which electrodes are most optimally in contactwith the scalp and gathering the clearest signal by comparing the signalquality from the electrodes. Electrodes in the vicinity with lowersignal quality may then be ignored. In addition, if an electrode has arelatively weak signal and an adjacent electrode has a stronger signal,the user or automated analyzer can utilize the stronger signal andignore the weaker signal. This enables the user or machine (e.g., theanalyzer) to virtually move the electrode to the stronger signalgathering position without having to physically adjust any mechanicalcomponents (i.e., without physically adjusting the location andorientation of the bands).

FIGS. 13A and 13B are cross-sectional views of example electrodes incontact with the scalp of a user. FIG. 13A shows a traditional electrode180 that is unable to penetrate a user's hair. Thus, the traditionalelectrode 180 does not make sufficient physical contact with the user'sscalp, which increases the impedance and reduces signal quality. In theexample of FIG. 13B, an electrode 182 is smaller and thinner than thetraditional electrode 180 and is dimensioned to penetrate the hair tocontact the scalp of a user directly without any hair strands and/orhair follicles underlying the electrode 182. The example electrode 182also includes a cover 184 (e.g., a shield) for shielding the electrodefrom electromagnetic interference (e.g., electromagnetic waves andnoise) from the environment. The example cover 184 of FIG. 13B issufficiently wide such that it cannot penetrate all the hair on a user'shead and, thus, enhances a user's comfort. However, in the illustratedexample, the electrode 182 is smaller and thinner than the cover 184 sothat the electrode 182 does penetrate the hair to contact the user'sscalp. Thus, the electrode 180 can compress at least a portion of thestrateum corneum. If the electrode is too thick, it will not be able topenetrate the hair of a user (as shown in the traditional electrode 180of FIG. 13A). If the electrode is too thin, and sticks out too far, theelectrode will create a sharp pain on the user's head. In the exampleshown in FIG. 13B, the electrode 182 has a diameter d₂ of about 0.5 mmand the cover 184 has an outside diameter d₁ of about 1 mm. In theexample of FIG. 13B the electrode 182 has length l₁ that extends about0.2 mm from the cover 184 to contact the scalp of a user. Because theelectrode 182 is able to make direct contact with the scalp without theinterference of hair, there is less impedance and less noise in a signalgathered from the electrode 182 than from the electrode 180 shown inFIG. 13A. Therefore, less shielding is needed. In general, the smallerthe diameter of the electrode in contact with the scalp, the morediscomfort a user may experience. However, if the distance betweenadjacent electrodes is decreased and/or the number of electrodes in aspecific area is increased, the force or tension applied to the headsetand, thus to the electrodes, is split amongst the electrodes, whichincreases comfort for the user and, thus may offset the effect of thesmall electrode points.

FIG. 14 is a circuit diagram 1400 of an example electrode to skincontact, which may represent, for example, Z_(E) of FIGS. 8A-C. Thecoupling between the skin and the electrode is a layered conductive andcapacitive structure represented by combinations of parallel resistorand capacitor (RC) elements connected in series. The parallel capacitorC_(d) 1402 and resistor R_(d) 1404 represent the coupling impedance ofthe double layer at the skin-electrode interface, and the parallelcapacitor C_(i) 1406 and resistor R_(i) 1408 represent the inputimpedance of the amplifier 1410. The resistor R_(s) 1412 represents theminimum series contact resistance and the voltage V_(pol) 1414represents the DC polarization potential of the body.

FIGS. 15 and 16 illustrate an alternative spine and electrodeconstructed in accordance with the teachings of this disclosure. Anexample band 1500 has a spine body 1502 and an elastic strap 1504 totighten the spine body 1502 against the head of a user. The spine body1502 includes a plurality of individual electrode units 1506, eachhaving a pair of leg-shaped electrodes 1508 and 1510 pivotably coupledto the unit 1506 and projecting downwards to aim the electrodes 1508 and1510 at the scalp of a user.

An exploded view of an example electrode unit 1506 is shown in FIG. 16.The electrode unit 1506 of the illustrated example includes theelectrodes 1508 and 1510, each of which includes a shaft 1512, 1514 anda contact ball 1516, 1518, respectively. Each of the electrodes 1508,1510 further comprises a mounting ring 1520, 1522, respectively. Themounting rings 1520, 1522 are disposed within an opening 1524 within ahousing 1526. The housing 1526 comprises a plate 1528 and sleeves 1530,1532. The mounting rings 1520, 1522 of the electrodes 1508, 1510 fitbetween the sleeves 1530, 1532. In the illustrated example, the shafts1512, 1514 protrude below the plate 1528 and are angled outward fromeach other to contact the scalp of a user. The electrodes 1508, 1510 arepivotably coupled the housing 1526 via respective pins 1534, 1536, whichare disposed through the sleeves 1530, 1532 and through the respectiveholes in the mounting rings 1520, 1522. In the example of FIG. 16, aspring 1538 is disposed between the mounting rings 1520, 1522 and thesleeves 1530, 1532. The spring 1538 includes tabs 1540, 1542. As theelectrode unit 1506 is tightened down toward the head, the electrodes1508, 1510 rotate and flex upward. The ends of the shafts 1512, 1514adjacent the mounting rings 1520, 1522 are pressed against therespective tabs 1540, 1542 of the spring 1538, which biases theelectrodes 1508, 1510 back down toward the head. The electrodes 1508,1510 flex and maintain a consistent pressure downward on the scalp of auser when force is applied to the electrode unit 1506. In theillustrated example, the spring 1538 comprises a nonconductive materialto keep the signals gathered from the first electrode 1508 separate fromthe signals gathered from the second electrode 1510.

The electrode unit 1506 of the illustrated example allows a user toeasily remove and replace individual electrodes. The top of the plate1528 includes a flexible PCB 1544, which communicatively couples theelectrodes 1508, 1510 to a processor for data processing. The PCB andthe electrodes 1508, 1510 may be coupled to the processor and/or anyother analysis unit via a wired or wireless connection. As shown in FIG.15, the band 1500 of the illustrated example includes multipleindividual electrode units 1506. Each electrode unit is hinged to theadjacent electrode unit, such that the entire band 1500 may curve aroundand lay against the head of a user.

FIG. 17 is an exploded view of another example electrode unit 1700constructed in accordance with the teachings of this disclosure. In thisexample, the electrodes 1702, 1704 are snap electrodes. Each of theelectrodes 1702, 1704 has a shaft 1706, 1708 and a contact ball 1710,1712, respectively. The first electrode 1702 has a top hook member 1714and a bottom hook member 1716. Likewise, the second electrode 1704 has atop hook member 1718 and a bottom hook member 1720. The example snapelectrode unit 1700 of the illustrated example further includes a firstconnector 1722, a second connector 1724, a flex board 1726, a back plate1728 and a front plate 1730. The first and second connectors 1722, 1724each include a vertical portion 1732, 1734, respectively, and ahorizontal portion 1736, 1738, respectively. Each of the first andsecond connectors 1722, 1724 further include two apertures 1740, 1742,1744, 1746, respectively. The vertical portions 1732, 1734 are sized tofit within respective ones of the top and bottom hook member, 1714,1716, 1718, 1720. The back plate 1728 includes a channel 1748 configuredto receive the flex board 1726. The front plate 1730 likewise has achannel 1750 to receive the flex board 1726. The back plate alsoincludes four pegs, 1752-1758. Two of the pegs 1752, 1754 aredimensioned to engage the apertures 1740, 1742 on the first connector1722. The other two pegs 1756, 1758 are dimensioned to engage theapertures 1744, 1746 on the second connector 1724. The front plate 1730of the illustrated example is operatively coupled to the opposite sideof the back plate 1728.

In operation, the snap electrode unit 1700 is pressed downward against auser's head. The downward force causes the shafts 1706, 1708 to pivotupwards. The top hook members 1714, 1718 rotate inward onto thehorizontal portions 1736, 1738, respectively, and, thus, against theflex board 1726. The flex board 1726 provides a reflective force so theelectrodes 1702, 1704 keep a consistent force against the scalp of auser. The flex board 1726 also serves as the PCB to propagate anysignals gathered from the electrodes 1702, 1704 to a processor and/orother analysis unit as disclosed herein.

FIG. 18 illustrates another example electrode 1800 constructed inaccordance with the teachings of this disclosure. In the illustratedexample, the electrode 1800 includes a wire band 1802 and a coilelectrode 1804. In the example of FIG. 18, the coil electrode 1804 is acoil of wire wrapped around the wire band 1802 and is positioned to lieagainst the scalp of a user. The individual coils of the coil electrode1804 will penetrate the hair of a user to make contact with the scalp.If the electrode 1804 rotates, the electrode 1804 will continuallymaintain contact with the scalp, and any signal being gathered will notbe lost.

FIGS. 19A and 19B illustrate another example electrode 1900 constructedin accordance with the teachings of this disclosure. In the illustratedexample, the electrode 1900 includes a wire band 1902 and a single curveelectrode 1904. FIG. 19B is a cross-sectional view of the electrode 1900of FIG. 19A. The single curve electrode 1904 of the illustrated examplehas two ball tips 1906, 1908 at the ends of the electrode 1904. Thesingle curve electrode 1904 curves over the wire band 1902 so that bothends are pointed downward and both the ball tips 1906, 1908 may contactthe scalp of a user. As the wire band 1902 is stretched or tightened,the electrode coupled thereto is also stretched, and the center portionof the electrode 1904 moves closer to the scalp to provide additionalpressure to the ball tips 1906, 1908 against the scalp.

FIG. 20 shows a mold 2000 that may be used for manufacturing a spine asshown and described in FIGS. 1-7. In the illustrated example, the mold2000 comprises a mold body 2002 and a mold cavity 2004. The mold cavity2004 defines the shape of a flat spine. In an example manufacturingprocedure, the PCB and electrodes are placed within the mold first, andthen liquid plastic or resin is injected into the cavity 2004 to formthe spine body. After the molding processing the spine is remove andformed to curve the individual extensions downward.

FIG. 21 shows multiple spines 2100, 2102, 2104 directly after molding inthe process described in connection with FIG. 20 and before the spinesare shaped. In the example of FIG. 21, the spines 2100, 2102, 2104comprise a plurality of electrodes 2106, 2108, 2110 protruding from thespines 2100, 2102, 2104. The ball electrodes 2106, 2108, 2110 may becurved downward. In this example, the ends of each spine 2100, 2102,2104 include a pin port 2112, 2114, 2116 for coupling the spine 2100,2102, 2104 to a processing unit to a headset.

FIGS. 22A-22J are perspective views of a user's head identifying optimumareas for electrode contact. As shown in these figures, there aremultiple electrode sites including, for example, twenty sites related tothe International 10-20 system. These sites provide coverage of all thelobes of the brain including frontal, parietal, occipital and temporal.These sites are the accepted EEG electrode sites for a clinically validEEG. The sites shown in FIGS. 22A-22J are selected to give broadcoverage and avoid sites with excessive muscle activity. In an exampleheadset with eighty channels, the twenty sites of the International10-20 system are covered as are additional sites over muscle. Forexample the eighty channel system provides predominant coverage tonon-muscle contaminated sites as well as covering muscle sites includedin the standard clinical EEG system.

FIG. 22J illustrates an example headset with five bands 2202-2210positioned on the head of a user for reading. The individual bands2202-2210 are adjustable and may be placed along specific paths tooptimize electrode placement. The example scheme of FIG. 22J bisects thehead into a left section and a right section by forming a line betweenthe nasion (between the eyes) to the inion (back of the head). A secondline bisects the head along a line from the left ear canal to the rightear canal. Each of these lines is further partitioned at intervals of10% and 20% of its distance. In the illustrated example, a firstelongated band 2202 is located above a nasion of the subject at aboutten percent of a distance between the nasion and an inion of the subjectmeasured over a center of a head of the subject. A second elongated band2204 is located above the nasion at about thirty percent of the distanceto the inion. A third elongated band 2206 is located at about halfwaybetween the nasion and the inion. A fourth elongated band 2208 islocated past the halfway point, e.g., closer to the inion than thenasion but more than thirty percent of the distance away from the inion.A fifth elongated band 2210 is located above the inion at about thirtypercent of the distance. This arrangement may optimize coverage of theentire head. In other examples, additional bands are included inpositions between the five illustrated bands. Still further, in otherexamples, the bands 2202-2210 are positioned at any other desired degreeof rotation depending on the desired readings and/or the quality ofelectrical contact between the electrodes and the scalp.

FIG. 23 illustrates an alternative example headset 2300 constructed inaccordance with the teachings of this disclosure for measuringelectrical activity at the scalp. The headset 2300 of this examplecomprises a main headband 2302, which curves over the top of the head ofa user. Multiple support bands having individual electrodes extend fromthe headband 2302 in multiple directions for positioning electrodes overmultiple locations on a user's head. The headset 2300 includes a lefthub 2304 and a right hub 2306, both of which are rotatably and removablycoupled to the ends of the headband 2302. In the illustrated example,the left hub 2304 includes seven support bands 2308-2320. The right hub2306 of the illustrated example also includes seven support bands2322-2334. However, in other examples, different number(s) of supportbands are used to increase, decrease and/or otherwise adjust the numberand/or location of electrode placement. In this example, each of thesupport bands 2308-2334 has a set length and two ends which are fixedlyand flexibly coupled to the left and right hubs 2304, 2306,respectively. In some examples, one or more of the lengths of thesupport bands 2308-2334 are adjustable. The headband 2302 furtherincludes front support bands 2336-2344 and rear bands 2346-2348. In thisexample, each of the supports bands 2336-2348 has a set length and isfixedly and flexibly attached on one end to the headband 2302. Also, insome examples, one or more of the lengths of the support bands 2336-2344are adjustable. The distal ends of all the support bands 2308-2348 areoperatively coupled to a respective electrode housing 2250 a-2250 u.Each housing 2250 a-2250 u houses an individual electrode 2352 a-2352 u,respectively. In some examples, one or more of the electrode housings2250 a-2250 u support a plurality of electrodes. In the illustratedexample, different ones of the support bands 2308-2348 have differentlengths to position the respective electrodes 2352 a-2352 u overdifferent locations on the scalp. The locations may be selected tooptimize detection of electrical activity in the brain. The supportbands 2308-2348 are curved slightly inward to apply sufficient force onthe head of a user to cause the respective electrode to press slightlyonto the scalp to reduce noise and increase the signal-to-noise ratio toenhance signal quality. Further, the support bands 2308-2348 in theillustrated example include a flexible plastic to enable each supportband 2308-2348 to flex when placed over the head of a user andaccordingly adjusts to different head sizes and applies a constantand/or sufficient force to the scalp for reading the electrical signalsof the brain. In the example shown in FIG. 23, the headset 2300 hastwenty-one support bands and twenty-one electrodes. However, in otherexamples the headset includes more or fewer support bands and/or mayinclude more than one electrode per support band.

Further, as shown in FIG. 23, the headset 2300 is couplable to a base2354 for storing the headset 2300 when not in use, for charging theheadset 2300 and/or for data transfer as disclosed in greater detailbelow. The base 2354 includes a generally vertically extending supportshaft 2356 to hold the headset 2300 above a support surface such as atable, desk or shelf. The base 2354 also includes a base plate 2358 tosupport the base 2354 in an upright position. In some examples, the base2354 transfers data via a wired connection to a data analyzer. In otherexamples, the base 2354 wirelessly transfers data.

FIG. 24 is a bottom view of the example headset 2300 of FIG. 23. Theheadband 2302 has a micro-USB port 2386 on the bottom for batterycharging and data transfer. The headset 2300 includes a battery withinthe central headband 2302 and/or within a housing such as, for example,a housing located near the sides of the head (see e.g., the housings3010, 3012 disclosed below in connection with FIG. 30, which may beincorporated into the example headset 2300 of FIG. 23). As seen in FIG.25, the base shaft 2356 of the base 2354 includes a male micro-USBconnector 2388, which may be inserted into micro-USB port 2386 forcharging the headset 2300 and/or transferring data from a headset-basedprocessor to a computer or a database for further processing. In otherexamples, any other suitable electrical and/or communication couplingmay be used including, for example, other types of physical ports and/ora wireless coupling.

FIGS. 26-29 are different views of the example headset 2300. As seen inFIGS. 26 and 27, the left and right hubs 2304, 2306 are rotatably andpivotally coupled to the ends of the headband 2302. The left hub 2304has an adjustment ball 2360 that fits within a left socket 2362 on theinside of the headband 2302. The adjustment ball 2360 and left socket2362 (i.e., ball and socket joint) allow the hub 2304 to rotate andpivot in any desired direction to position the support bands 2308-2320over desired locations on the left side of a user's head. The right hub2306 also has an adjustment ball 2364 that is designed to fit within aright socket 2366 on the headband 2302. Thus, the right hub 2306 also iscoupled to the headband via a ball and socket joint to enable the hub2304 to rotate and pivot in any desired position. FIG. 28 shows theheadband 2302 slightly curved to the back such that the headset 2300 issupported at a crown of the head while the left and right hubs 2304,2306 are positioned near the left and right ear, respectively.

FIG. 29 is a bottom view of the headset 2300 and shows that the headset2300 includes a pad 2368 that provides comfort to the user and also maybe used to provide stability to the headset 2300 so that the headset2300 maintains its position as the user moves his or her head.Increasing the stability of the headset 2300 also decreases any noisethat may be generated by friction caused by movement of the electrodesalong the scalp of the user. In addition, the pad 2368 may double as ahousing that encases electrical components such as, for example, aprocessor, which may, for example, comprises hardware, firmware and/orsoftware for processing the signals from the electrodes, converting theelectroencephalographic data from analog data to digital data,amplifying the electroencephalographic data, removing noise from thedata, analyzing the data, and/or transmitting the data to a computer orother network. The headset 2300 comprises a printable circuit board 2370that is disposed within the headband 2302 and the support bands2308-2344 to communicatively couple the electrodes 2352 a-2352 u to theprocessor for processing. Also, in some examples, the housing 2368 mayencase a power supply such as, for example, one or more batteries.

FIG. 30 illustrates an exploded view of example layers for an exampleheadset 3000. Though an alternative shape is shown in FIG. 30, thelayering concepts shown in FIG. 30 may be used for any suitable headsetstructure including, for example, the headset 100 of FIG. 1, the headset1500 of FIG. 15, a headset created in the mold 2000 of FIG. 20, theheadset 2300 of FIG. 23 and/or other suitable headset. The first layer3002 comprises a plastic and/or metal housing layer. The first layer3002 provides tension and shape to the headset 3000 as well as theflexibility needed to adjust the headset and apply sufficient pressureat each electrode to optimize signal gathering. The dimensions (e.g.,width) of each arm in the layer is specifically designed for aparticular tension (e.g., to optimize performance). The second layer3004 is the flexible circuit board that is used to transmit datagathered at each electrode to the electronics/processor. The headset3000 includes a third layer 3006 and fourth layer 3008 at each end. Thethird layer 3006 corresponds to the material of the first layer 3002 andthe fourth layer 3008 corresponds to the material of the second layer3004. The first layer 3002 and the third layer 3006 provide shielding tothe signals as the signals propagate along the second layer 3004 and thefourth layer 3008. Also, the material used may be selected to enhanceshielding for the flexible PCB and electromagnetic interferenceshielding for the example systems. Also, the PCBs of the second layer3004 and fourth layer 3008 are flexible and thin and include thin wiringthat has low impedance and low capacitance, which reduces loss duringsignal propagation.

The headset 3000 also includes a first housing 3010 and a second housing3012. An example of the first and second housing is shown in greaterdetail in FIG. 31. Each housing includes a cover 3014 and a support ring3016. The electronic components and processor are supported in one ofmore of the housings 3010, 3012. Additionally or alternatively, in someexamples, an adjustment mechanism such as, for example, the adjustmentmechanism of FIG. 9 is supported by one or more the housings. Though anoval shape is shown in FIGS. 30 and 31, any suitable shape may be usedfor the housings.

FIGS. 32A and 32B illustrate top and bottom perspective views of anexample snap electrode unit 2372. The snap electrode unit 2372 comprisesback plate 2374 and an electrode layer 2376. The electrode layer 2376may comprise a silver coated electrode or an electrode coated with ormade from any suitable conductor. The back plate 2374 has a shaft 2378,which extends through the PCB 2370 and support band 2390 into the backof the electrode 2376 to couple the electrode 2376 to the PCB 2370 andthe support band 2390. The electrode may be readily assembled with theback plate or disassembled from the back plate to facilitate replacementof the electrodes. FIGS. 32C and 32D illustrate a snap electrode unit2372 with an alternative contact electrode 2380.

FIG. 33 is an enlarged view of the example electrode housing 2350 andthe example electrode unit 2352 of FIG. 23. As shown in FIG. 33, thehousing encloses the back plate 2374 (shown in FIGS. 32A-32D) but theshaft 2378 extends from the housing to receive the electrode. In theillustrated example, the electrode unit 2352 includes an alternativeelongated electrode 2382. In other examples, the electrode has any othershape or size appropriate to contact the scalp of a user to receiveelectrical signals.

FIG. 34 is a perspective view of an example net array headset 3400. Thenet array headset 3400 includes a plurality of elastic bands 3402 a-3402m that forms a zig-zag or criss-cross pattern. An electrode 3404 a-3404t is located at each intersection of the elastic bands 3402 a-3402 m. Aplurality of the elastic bands 3402 a-3402 g converges in the back ofthe net array headset 3400 and is coupled to an adjustment knob 3406. Asthe adjustment knob 3406 is turned, the individual elastic bands 3402a-3402 m (and others unnumbered) are pulled tight and the electrodes3404 a-3404 c (and others unnumbered) are forced downward onto the scalpof a user. The adjustment knob 3406 allows the net array headset 3400 tobe adjustably used on a range of differently sized heads. As shown inFIG. 35 the adjustment knob 3406 is rotatable to wind up the individualelastic bands 3402 a-3402 g and, thus, tighten the net array headset3400 onto the head of a user. The net array headset 3400 enhances thefit of electrodes on differently shaped heads and produces a light andportable headset.

FIG. 36 is a block diagram of an example processing system 3600 for usewith any of the headsets disclosed herein. The example system 3600includes a plurality of electrodes 3602. The electrodes 3602 arecoupled, for example, to a headset to be worn on a head of a subject. Insome examples, the headset includes a plurality of elongated bands thatextend between a first housing located near a first ear of a subject anda second housing located near a second ear of the subject. In someexamples, one or more of the elongated bands is rotatably and/orremovably coupled to each of the first and second housings such that theelectrodes 3602 can be moved to different positions on the head and/orremoved from the headset. The headset may include numerous channels ofelectrodes such that multiple (e.g., 2000 or more) electrodes areincluded in the example system 3600. In addition, in some examples, thepressure applied on the head by each electrode may be adjusted byadjusting an elastic band or strap associated with each of the elongatedbands.

The electrodes may have any suitable shape such as, for example, atleast a portion of a ring, a ball, a hook and/or an array. Theelectrodes 3602 may include one or more of the properties of any of theelectrodes disclosed in this patent. In addition, different types ofelectrodes may be included in the system 3600. Also, in some examples,the electrodes 3602, and the elongated bands to which the electrodes3602 are coupled, have a protective covering such as, for example, anylon and/or a silver mesh. In some examples, the covering is astretchable silver-coated nylon mesh. The covering provides additionalshielding and protection. In addition, the electrodes 3602 including thecovering may be machine washable.

The example electrodes 3602 may also be adjustably mechanically coupled,such as for example, via the elongated bands to a first housing where anadjustable locking mechanism is supported to releasably hold theelongated bands and, thus, the electrodes 3602 in one or multiplepositions. An example locking mechanism includes the magnetic lockdisclosed above.

The electrodes 3602 are also communicatively coupled to a second housing(e.g., the second housing 128 of the headset 100 shown in FIG. 1) thatsupports an electrical processing unit 3604 via a communication line3606, which may be for example a wired or wireless communication linkincluding, for example, the PCB communication channels disclosed above.The example processing unit 3604 includes an analog-to-digital converter3608, a signal conditioner 3610, a database 3612, an analyzer 3614 and atransmitter 3616.

The analog-to-digital converter 3608 converts the analog signalsreceived at the electrodes 3602 to digital signals. In some examples,the analog-to-digital converter 3608 is located in the processing unit3604 at one of the housings of the headset. In other examples, theanalog-to-digital converter 3608 comprises multiple A-D converterslocated to service individual or sets of the electrodes to convert thesignals as close to the source as possible, which may further reduceinterference.

The signal conditioner 3610 of the illustrated example prepares thegathered signals so that the data is in a more usable form. For example,the signal conditioner 3610 may include an amplifier to amplify thesignal to a more detectable level. In addition, the signal conditioner3610 may include a filter to remove noise from the signal. The filtermay also be used as a bandpass filter to pass one or more frequencybands and/or manipulate select bands depending on the desired processingand/or analysis. For example, in analyses to study only the alpha waves,the signal conditioner may be programmed to present only thosefrequencies between about 7.5 and about 13 Hz. In some examples, each ofthe electrodes 3602 may include a signal conditioner at or near theelectrode 3602. The example signal conditioner 3610 may include hardwareand/or software to execute a signal conditioning method. In someexamples, the signal conditioner includes a detrending unit tocompensate for electrode polarization, in which there is slow movementof the voltage signal unrelated to brain wave activity due topolarization of the electrodes. The example processing unit 3604 alsoprovides signal processing that may include hardware and/or software toexecute Fast Fourier Transform (FFT) measurements, coherencemeasurements and/or custom adaptive filtering.

The analyzer 3614 is to analyze the data gathered from the electrodes3602 and processed by the analog-to-digital converter 3608 and thesignal conditioner 3610 in accordance with one or more analysisprotocols depending on the desired study. For example, in accordancewith some studies, the analyzer 3614 may process the data to determineone or more of a subject's mental state, physiological state, attention,resonance or memory, emotional engagement and/or other suitablecharacteristics of the subject.

The transmitter 3616 communicates the data at any stage of processingand/or the results of the analysis from the analyzer 3614 to an output3618. The output 3618 could be a handheld device, an alarm, a displayscreen on the headset, a remote server, a remote computer and/or anyother suitable output. Data transmission may be implemented by Bluetoothtransmission, wi-fi transmission, ZiGBee transmission and/or proprietaryencryption before transmission. In the illustrated example, the database3612 stores all data gathered streams. The streams can be buffered forstreaming or stored on-board (i.e., at the headset) for periodic oraperiodic uploads during, for example, low-activity periods.

The processing unit 3604 components 3608-3616 are communicativelycoupled to other components of the example system 3600 via communicationlinks 3620. The communication links 3620 may be any type of wiredconnection (e.g., a databus, a USB connection, etc.) or a wirelesscommunication mechanism (e.g., radio frequency, infrared, etc.) usingany past, present or future communication protocol (e.g., Bluetooth, USB2.0, USB 3.0, etc.). Also, the components of the example system 3600 maybe integrated in one device or distributed over two or more devices.

While example manner of implementing the system 3600 has beenillustrated in FIG. 36, one or more of the elements, processes and/ordevices illustrated in FIG. 36 may be combined, divided, re-arranged,omitted, eliminated and/or implemented in any other way. Further, theexample signal conditioner 3610, the example A/D converter 3608, theexample database 3612, the example transmitter 3616, the exampleanalyzer 3614, the example output 3618 and/or, more generally, theexample system 3600 of FIG. 36 may be implemented by hardware, software,firmware and/or any combination of hardware, software and/or firmware.Thus, for example, the example signal conditioner 3610, the example A/Dconverter 3608, the example database 3612, the example transmitter 3616,the example analyzer 3614, the example output 3618 and/or, moregenerally, the example system 3600 of FIG. 36 could be implemented byone or more circuit(s), programmable processor(s), application specificintegrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s))and/or field programmable logic device(s) (FPLD(s)), etc. When any ofthe apparatus or system claims of this patent are read to cover a purelysoftware and/or firmware implementation, at least one of the examplesignal conditioner 3610, the example A/D converter 3608 or the exampledatabase 3612 are hereby expressly defined to include hardware and/or atangible computer readable medium such as a memory, DVD, CD, etc.storing the software and/or firmware. Further still, the example system3600 of FIG. 36 may include one or more elements, processes and/ordevices in addition to, or instead of, those illustrated in FIG. 36,and/or may include more than one of any or all of the illustratedelements, processes and devices.

FIG. 37 illustrates another example system 3700 that may be implemented,for example, by one or more of the example headsets 100, 2300, 3400shown in FIGS. 1, 23 and 34. The example system 3700 of FIG. 37 may beused to enhance signal strength by, for example, shorting out one ormore electrodes to effectively increase a surface area of an electrodeusing, for example, the example circuit 300 of FIG. 12A. Increasingsurface area lowers the impedance and improves the signal-to-noise ratioof the data gathered at the electrode. In addition, the example system3700 may be used to virtually move an electrode by selecting one or moreinput channels to choose more effective electrode locations occupied byelectrodes obtaining high quality and less noisy signals. Theseelectrodes may be, for example, the electrodes that have optimum or nearoptimum contact with the scalp. The system 3700 enables a user or anoperator to discard electrodes that are inoperable, mis-operating orinsufficiently coupled to the scalp and/or the remainder of the headset.

The example system 3700 of FIG. 37 includes any number of input channels(e.g., a first input channel 3702, a second input channel 3704, a thirdinput channel 3706, a fourth input channel 3708 . . . n input channels3710). For example, as disclosed above, one or more of the headsetsdisclosed herein may include 2000 or more input channels. In thisexample, the input channels 3702-3710 are each associated with anelectrode. In other examples, one or more of the input channels3702-3710 may be associated with other type(s) of sensor(s) such as, forexample, an eye tracker, a galvanic skin response sensor, a breath ratesensor, a thermometer, a sphygmomanometer to measure blood pressure, afunctional magnetic resonance imaging sensor and/or other suitable typesof sensors. Such sensor(s) may be freely added or removed. Somesensor(s) may be added to the headset itself, and other sensor(s) may becoupled to an arm, a chest or other body part and communicativelycoupled to the headset.

The example system 3700 of FIG. 37 includes an analyzer 3712. In theillustrated example, the analyzer 3712 is implemented by a programmedprocessor. The example analyzer 1712 of FIG. 37 includes an evaluator3714, a conditioner 3716 and a selector 3718. In some examples, one ormore of the components 3714-3718 of the analyzer 3712 are incorporatedinto a housing such as, for example, the second housing 128 of theheadset 100 shown in FIGS. 1-3. In other examples, one or more of thecomponents 3714-3718 of the analyzer 3712 are incorporated into ahandheld device, a local computer, a remote server or other suitabledevice. The evaluator 3714 evaluates the properties of the incomingsignals, such as for example, strength, amplitude, signal-to-noiseratio, duration, stability and/or other suitable signal characteristicsindicative of the integrity of the data and/or the quality of theconnection between the headset and the scalp. Example methods todetermine what signals are acceptable include, for example, comparingone or more aspects of a signal from a given electrode (e.g., itsamplitude, frequency, etc.) to one or more of an absolute threshold, aspectral threshold, a ramp-rate threshold, a low-activity (flat)threshold and/or performing a neighborhood correlation between thesignal of a given electrode and signals from one or more otherelectrodes near the given electrode.

The example conditioner 3716 of the illustrated example amplifies and/orfilters the signal to improve signal quality. If the conditioner 3716enhances the quality of a signal to acceptable levels such that thesignal is usable, the evaluator 3714 of the illustrated exampledetermines that the integrity of data from the associated electrode isacceptable and that the data does not need to be discarded and/or thatthe data from the electrode does need to be ignored or discarded.

The selector 3718 of the illustrated example selects which inputchannels to ignore, use, and/or merge (e.g., average) to improve (e.g.,optimize) the overall input based on the determinations of the evaluator3714. The plurality of input channels 3702-3710 are communicativelycoupled to the analyzer 3712 and corresponding components 3714-3718 viacommunication links 3720 (e.g., any wired or wireless communicationlinks).

In the example system 3700 shown in FIG. 37, the example evaluator 3714determines which of the input channels 3702-3710 (e.g., electrodes) arecollecting the best, most useful, and/or most accurate data. Based onthis determination, the example selector 3718 identifies whichelectrodes/input channels are most effective (e.g. for the best EEGreadings) and which electrodes/input channels should be ignored toimprove the readings. Ignoring an electrode/communication may involvedisabling the channel (e.g., via a switching circuit) and/or ignoringthe data it collects. Disabling an electrode effectively increases thesurface area contact between one or more electrodes adjacent thedisabled electrode and the tissue on the scalp. Disabling oneelectrode/channel can be referred to as shorting out the electrode. Byshorting out an input channel (e.g., effectively increasing theeffective surface area of another electrode at an adjacent inputchannel), the overall impedance of the channels is lowered and signalquality is improved. Lower impedance and better signal-to-noise ratioenables the example system 3700 of FIG. 37 to read higher frequencybands. Selection of which electrode(s) are candidates for shorting isbased on regional coverage and data quality. For example, if there isincreased noise in multiple electrodes in a small neighborhood ofelectrodes, some or all of such electrodes can be shorted to improve thesignal to noise ratio. Furthermore, with a large number of inputchannels, the selector 3718 may determine which electrodes are in bestcontact with the scalp and gathering the clearest signal. Otherelectrodes in the vicinity may be ignored and/or shorted out with aswitching circuit 300 (FIG. 12A), 3722 (FIG. 37). In addition, if aninput channel provides a relatively weak signal and an adjacent inputchannel provides a stronger signal, the selector 3718 emphasizes theinput channel with the stronger signal by deselecting the channel withthe weaker signal. Deselecting a signal (e.g., disabling it via theswitching circuit 3722) and relying on the data collected by adjacentelectrodes can be thought of as moving the function of the deselectedelectrode to the adjacent electrode. Thus, the example system 3700 ofFIG. 37 can virtually move an electrode to a stronger signal gatheringposition without having to physically adjust any mechanical components(i.e., without physically moving the electrode over).

While example manner of implementing the system 3700 has beenillustrated in FIG. 37, one or more of the elements, processes and/ordevices illustrated in FIG. 37 may be combined, divided, re-arranged,omitted, eliminated and/or implemented in any other way. Further, theexample analyzer 3712, the example evaluator 3714, the exampleconditioner 3716, the example selector 3718, the example switchingcircuit and/or, more generally, the example system 3700 of FIG. 37 maybe implemented by hardware, software, firmware and/or any combination ofhardware, software and/or firmware. Thus, for example, the exampleanalyzer 3712, the example evaluator 3714, the example conditioner 3716,the example selector 3718, the example switching circuit 3720 and/or,more generally, the example system 3700 of FIG. 37 could be implementedby one or more circuit(s), programmable processor(s), applicationspecific integrated circuit(s) (ASIC(s)), programmable logic device(s)(PLD(s)) and/or field programmable logic device(s) (FPLD(s)), etc. Whenany of the apparatus or system claims of this patent are read to cover apurely software and/or firmware implementation, at least one of theexample analyzer 3712, the example evaluator 3714, the exampleconditioner 3716, the example selector 3718 or the example switchingcircuit 3720 are hereby expressly defined to include hardware and/or atangible computer readable medium such as a memory, DVD, CD, etc.storing the software and/or firmware. Further still, the example system3700 of FIG. 37 may include one or more elements, processes and/ordevices in addition to, or instead of, those illustrated in FIG. 37and/or may include more than one of any or all of the illustratedelements, processes and devices.

FIG. 38 illustrates an example system 3800 that includes a headset 3812,which is representative of one or more of the example headsets and/orsystems described herein, such as, for example, the headset 100 of FIG.1, the headset 2300 of FIG. 23, the headset 3400 of FIG. 34, the system3600 of FIG. 36, the system 3700 of FIG. 37 and/or the system 3900 ofFIG. 39 (disclosed below) with additional physiological senor(s). Theexample system 3800 may be used for in-home patient monitoring,treatment and/or diagnosis of medical conditions, to detectlife-threatening situations, to ascertain patient compliance with aprescribed medical regime and/or other suitable applications. Currentlypatients need to go to the hospital for neurological monitoring. Thisentails increased risk of exposure to hospital pathogens (such as, e.g.,acquired bacterial infections). However, in a hospital environment,there are skilled technicians to monitor the data, detect issues andalarm medical staff. Though there is no guarantee that data of interestdefining neurological status will not be missed. In the homeenvironment, the example headsets and/or systems disclosed hereinautomatically monitor the data, detect issues, and alarm the patient, anemergency call center, paramedics, a doctor and/or a local hospital ifthere are medical issues and/or emergencies. For example, a patient mayhave an aura (warning) of a seizure at home and not have time to get tothe hospital for monitoring. A self-applied, home EEG monitoring systemincluding the examples headsets disclosed herein enable the capture thisinformation critical for appropriate care. In addition, theself-application systems disclosed herein enable a patient to transmitdata, question(s), communication(s) and/or other information to amedical care professional when the patient feels there is somethingsymptomatically wrong with their physiology including, for example,underperformance in the cognitive domain. Furthermore, hospitals haveskilled technicians to monitor data quality and equipment function.Examples disclosed herein automatically perform those functions, therebyachieving cost savings and reducing the possibility of human error.

Also, the headsets and/or systems produce data that may be used withtelecommunication and/or other information technologies to provideclinical health care from a remote location. For example, a patient maybe examined and/or monitored by sending sensor data to a remote doctoror physician. In some examples, EKG data may be monitored such as, forexample, 24 hour at home monitoring of cardiac arrhythmia patients. Insuch examples, an EKG sensor is attached to the in-home patient wherebythe system is coupled to a phone line, the internet or othercommunication link. The EKG readings are transmitted directly to thepatient's cardiologist (and/or a technician, nurse, etc.) over thecommunication link. The example system 3800 of FIG. 38 is usable formany type(s) of patients with many type(s) of conditions includingcardiac arrhythmia, epileptic seizures, stroke, small vessel disease,dementia, memory loss, Alzheimer's, glucose monitoring, blood pressure,hypertonia, cognitive decline, depression and/or other conditions. Otherphysiological conditions, psychiatric conditions, disease progression,disease intervention effectiveness and/or developmental disorders arealso monitorable with the system, 3800 such as, for example, bipolardisorder, schizophrenia, attention deficit hyperactivity disorder (ADHD)and/or autism.

With respect to EEG data and the headsets used to gather the data,traditional systems have been uncomfortable to wear, require messy gels,are costly to manufacture and/or require extensive training to use.Example headsets 100, 2300, 3400, 3812 disclosed herein are useful(e.g., optimal) for in-home patient monitoring because such disclosedheadsets 100, 2300, 3400, 3812 are comfortable to wear, easy to operate,provide effective electrode-to-tissue contact, comprise a large numberof electrodes and/or are adjustable to accommodate differently sizedheads. In some examples, data from the example headsets 100, 2300, 3400,3812 is processed at the headset and transmitted to an off-sitemonitoring station for analysis by medical personnel (e.g., a doctor orphysician). In some examples, data storage occurs at the headset, at aremote data center or a combination thereof.

The example headsets 100, 2300, 3400, 3812 disclosed herein arecombinable with additional biometric, neurological and/or physiologicalsystem(s) to monitor, examine, treat and/or diagnosis multiple medicalconditions including physiological conditions and/or mental conditions.In the example system 3800, data from an EEG system 3802 is combined andaggregated with data from an EKG system 3804, a glucose monitoringsystem 3806, an EOG system 3808, a facial monitoring system 3809 and/orany other plug-in/play-and-play system 3810 (e.g., installable orcouplable programs and/or devices to add additional functionality), suchas for example, eye-tracking sensor(s) (e.g., the eye tracking sensor3910 of FIG. 39), galvanic skin response (GSR) signal(s), EMG signal(s),camera(s), infrared sensor(s), interaction speed detector(s), touchsensor(s) and/or any other sensor capable of outputting physiologicaland/or neurological data to the headset 3812 or directly to the off-sitemonitoring station. In addition, in some examples, the example facialmonitoring system 3809 includes to have a full facial and/or hemifacialcoverage camera to enable facial affect coding (FACS), which allowscategorization of facial expressions. In some examples, the examplefacial monitoring system 3809 includes a camera coupled to a telescopicboom.

In the illustrated example, the headset 3812 includes the EEG system3802, a local analyzer 3814 (which, for example, may be incorporatedinto the second housing 128 of the headset 100 of FIG. 1), an output3816 and a manual input 3818. In the illustrated example, thesub-systems 3802-3810 are communicatively coupled the headset 3812 and,thus, the local analyzer 3814 via communication link 3820, which mayinclude hard wire and/or wireless technology. Also, in some examples,one or more the sub-systems 3802-3810 may be incorporated into theheadset itself (e.g., the EOG system 3808 and/or the facial monitoringsystem 3809).

Each of the signals from the different sub-systems 3802-3810 representsan input. Each input may be filtered, conditioned and/or processed toformulate an output representing one or more properties orcharacteristics of the patient's condition. In the illustrated example,the EKG system 3804 is coupled to a patient's chest, and the EKG data iswirelessly sent to the EEG headset 3812. The EKG data is processed bythe local analyzer 3814 and sent to a remote facility 3822 fortreatment, diagnosis and/or monitoring of the patient. The remotelocation may be, for example, a doctor's office, a hospital, a clinic, alaboratory, an archive, a research facility and/or any other diagnosticfacility. The local analyzer 3814 may be communicatively coupled to theremote facility via a communication channel 3824 such as commontelephone line, landline, an internet connection, radio waves, and/orany other communication technology capable of sending signals. In theexample shown in FIG. 38, the local analyzer 3814 includes a clock 3826and a database 3828. The clock 3826 of the illustrated example timestamps the data for use, for example, in monitoring the progress of acondition or a treatment and/or generating medical records. The database3828 of the illustrated example is used for local storage.

In the example shown in FIG. 38, the local analyzer 3814 creates theoutput 3816. The output 3816 may be, for example, a light, a sound, adisplay and/or any other output that may be used, for example, to alerta patient of a need to seek medical attention, to take a dosage ofmedicine, to start an activity, to stop an activity, to eat somethingand/or any other suitable warning and/or command. In some examples, theoutput 3816 is operatively coupled to an auto-delivery system forautomatically delivering medicine to a patient in response to certainreadings from the system 3800. Diabetic patients, for example, oftenrequire continuous glucose and blood pressure monitoring. The examplesystem 3800 may monitor and deliver insulin automatically to a patientbased on the measured physiological characteristics. In the exampleshown, the output 3816 (e.g., a light, a speaker, a display, anauto-delivery system) is incorporated into the headset 3812. In otherexamples, the output 3816 may be separate from the headset 3812, and theheadset may communicate with the output 3816 via the wired or wirelesscommunication links disclosed herein.

The example system 3800 maybe be used to detect and/or treat psychiatricconditions such as, for example, depression. For example, a patient'sbrain waves may be monitored by headset 3812 via the EEG sub-system3802. If the local analyzer 3814 detects that the patient is becomingmore depressed, then small doses of anti-depressants may beautomatically injected and/or the output 3816 may sound an audiblemessage or alarm that directs the patient to self-administer a dosage ofmedicine. Alternatively, the output signal 3816 may be communicativelycoupled to a remote monitoring station such as a doctor's pager, suchthat when certain readings indicate that the patient has developed adangerous condition, a doctor is paged to respond and/or an alarm is setto direct the patient to seek medical attention.

Another benefit to the at-home system 3800 is the volume andcompleteness of patient data due to the continual recording andmeasuring of patient vitals and/or other physiological and/orneurological condition(s). Commonly, people are asked what they weredoing just before and after an occurrence of a medical event, such asfor example, a seizure. Patients often experience difficulty trackingand/or recalling their day-to-day activities with such precision.However, with the example system 3800, the local analyzer 3814 recordsthe patient's statistics and/or activities. The example self-applicationsystems disclosed herein enable the development of daily logs or flowcharts of brain activity, which is usable to identify relationshipsamong and/or trends in behavior, medication and physiologicalperformance. Also, in some examples, the headset is provided withgeographic tracking technology (e.g., GPS, etc.) to identify where apatient is located (e.g., the kitchen, a neighbor's home, the livingroom, etc.) at certain times. In some examples, the local analyzer 3814prompts the patient to enter his or her daily activity periodically oras specific medical events occur such as, for example, as spikes in oneor more readings occur. The example system 3800 of FIG. 38 includes themanual input 3818 to facilitate patient entry of such information. Insome examples, the manual input 3818 is carried by the headset 3812. Forexample, the manual input 3818 may be an interactive (e.g., touch)screen, a microphone and/or a keypad on a surface of the headset 3812.In other examples, the manual input 3818 could be a remote device suchas, for example, a handheld device, a computer, a mobile phone, a tabletand/or a television that is communicatively coupled to the system 3800.

Thus, the examples disclosed herein enable the collection, recordation,charting and/or development of baseline activity and a comparison ofpatient activity to the baseline on an on-going basis. The baselinedevelopment is patient-specific based on the volume of gathered data.Therefore, the baseline is not based on societal norms or averages, butrather, is shiftable and adaptable to the individual patient. Theexample systems and headsets disclosed herein also include on-boardstorage, processor, time tracking and spectral tracking to enablecontinuous charting/status evaluation for patients, medication usageand/or feedback improvement applications to increase patient complianceand/or response. In some examples, the self-application systemsdisclosed herein also provide prompts on/in response to potentialsalient events. For example, the examples disclosed herein can prompt toa patient to go see a physician if needed. In some examples, the promptsare based on changes in mental states and/or activities and/orsignificant deviations from the individual patient's norms such that theresponse or action prompt is tailored to the specific individual.

The volume and completeness of data collected by the example system 3800enable the development of real-time reports that provide effective datain diagnosing and treating medical conditions. For example, a patientwith ADHD may have a reading that indicates he/she is having increasedbrain activity in certain regions of the brain associated with lack ofconcentration. In response, the local analyzer 3814 may prompt the uservia the manual input 3818 to enter what he/she was recently doing (e.g.,drinking a can of cola). In another example, a depressed patient mayhave a reading indicating he/she is cheerful and happy. The localanalyzer 3814 will prompt the patient to record what he/she was doingjust prior to the reading. Such activity may be incorporated into atreatment plan to assist the patient in maintaining a desired mentalstate (e.g., happiness). In another example, a person with high bloodpressure may be monitored. If his/her blood pressure increased, thepatient may be asked what he or she ate or drank just prior the reading.Therefore, with the example system 3800, a patient can readily inputdata, and the physician can interpret the data and more accuratelydiagnosis health conditions and/or activities that affect suchconditions.

While example manners of implementing the system 3800 have beenillustrated in FIG. 38, one or more of the elements, processes and/ordevices illustrated in FIG. 38 may be combined, divided, re-arranged,omitted, eliminated and/or implemented in any other way. Further, theexample local analyzer 3814, the example clock 3826, the exampledatabase 3828, the example output 3816, the example manual input 3818,the example EEG sub-system 3802, the example EKG sub-system 3804, theexample glucose monitoring sub-system 3806, the example EOG sub-system3808, the example facial monitoring system 3809, the exampleplug-in/plug-and-play 3810 and/or, more generally, the example system3800 of FIG. 38 may be implemented by hardware, software, firmwareand/or any combination of hardware, software and/or firmware. Thus, forexample, the example local analyzer 3814, the example clock 3826, theexample database 3828, the example output 3816, the example manual input3818, the example EEG sub-system 3802, the example EKG sub-system 3804,the example glucose monitoring sub-system 3806, the example EOGsub-system 3808, the example facial monitoring system 3809, the exampleplug-in/plug-and-play 3810 and/or, more generally, the example system3800 of FIG. 38 could be implemented by one or more circuit(s),programmable processor(s), application specific integrated circuit(s)(ASIC(s)), programmable logic device(s) (PLD(s)) and/or fieldprogrammable logic device(s) (FPLD(s)), etc. When any of the apparatusor system claims of this patent are read to cover a purely softwareand/or firmware implementation, at least one of the example localanalyzer 3814, the example clock 3826, the example database 3828, theexample output 3816, the example manual input 3818, the example EEGsub-system 3802, the example EKG sub-system 3804, the example glucosemonitoring sub-system 3806, the example EOG sub-system 3808, the examplefacial monitoring system 3809 or the example plug-in/plug-and-play 3810are hereby expressly defined to include hardware and/or a tangiblecomputer readable medium such as a memory, DVD, CD, etc. storing thesoftware and/or firmware. Further still, the example system 3800 of FIG.38 may include one or more elements, processes and/or devices inaddition to, or instead of, those illustrated in FIG. 38, and/or mayinclude more than one of any or all of the illustrated elements,processes and devices.

FIG. 39 illustrates an example attention and control system 3900 thatmay be used for determining, processing and/or evaluating a user'sattention to media and/or to manipulate an input on an externalelectrical device without physical movement, (e.g., by using only theuser's mind). The example system 3900 includes a headset 3902, which maybe implemented for example, with the example headsets and/or systemsdisclosed herein such as, for example, the headset 100 of FIG. 1, theheadset 2300 of FIG. 23, and/or the headset 3400 of FIG. 34. The headset3902 processes EEG signals and/or other sensor data to develop a pictureof a mental state of a user including, for example, an emotional state,a state of engagement, a state of attention and/or any otherneurological state. As disclosed below, the example system 3900 of FIG.39 may be used to determine if the user is paying attention to a mediaprogram, to determine where a users eyes are focused, to determine thatthe user wants to control a remote device and effect that control (e.g.,change the volume on a television), and/or for other applications. Inthe illustrated example system 3900, the headset 3902 includes analyzercomponents including an EEG sensor 3904, a program identifier 3906, aremote action evaluator 3908, an eye tracker sensor 3910, anaccelerometer 3911, an attention evaluator 3912, a database 3914 and atransmitter 3916. The analyzer components 3904-3914 are communicativelycoupled via a communication link 3918 such as, for example, anycommunication described above. The analyzer components 3904-3914 may be,for example, incorporated into or otherwise supported by the headset3902 such as the headset 100 shown in FIG. 1, the headset 2300 shown inFIG. 23 or the headset 3400 shown in FIG. 34. In some examples, theanalyzer components 3904-3916 are housed in a compartment on a headset,such as, for example, the second housing 128 of the headset 100 shown inFIGS. 1-3.

As disclosed above example headsets 100, 2300, 3400 include a pluralityof individual electrodes to detect electrical activity along the scalpof a user. This data may be used to determine attention, memory, focusand/or other neurological states. The EEG sensor 3904 of the example ofFIG. 39 is implemented by the electrodes of the headsets disclosedabove.

The example eye tracker sensor 3910 is used to track eye movement and/orthe direction in which a user's eyes are directed. For example, the eyetracker sensor 3910 may be a camera or other sensor that is incorporatedinto an appendage that extends from the headset 3902 and is directed toone or both of the user's eyes. In other examples, the eye trackersensor 3910 may be a camera or other sensor on or near a computer, atelevision, a mobile phone screen or other location to gather datarelated to the user's eye movement. The eye tracker sensor 3910 maycontinuously record what the subject is seeing. In some examples, theeye tracker sensor is placed around the middle of the subject'seyebrows. Also, in some examples, the eye tracker sensor includes amonocular or binocular (e.g., one eye or two eye coverage) infra-red(IR) camera to track the pupil and/or corneal reflection positions toaide in determining a point of regard of the subject's viewpoint. Insome examples, the eye tracker sensor 3910 incorporates and/or is usedin conjunction with an accelerometer/attitude measurement system 3911.Many mobile eye-tracking systems that are mounted to a subject's headare susceptible to erroneous measurements as the subject moves his orher head relative to the position he or she had during calibration ofthe system. The example accelerometer 3911 continuously tracks therelative eye position from calibration, which enhance the accuracy ofthe point-of-regard measurement from the eye-tracking sensor 3910.

The eye track data may be synchronized with and/or otherwise used tocorroborate the EEG data or otherwise may be used in conjunction withthe EEG to determine a neurological state of the user. Eye movementsprovide a target of a user's attention allocation. For example, if theuser is looking in the direction of a television and his or her EEG dataindicates that he or she is in a state of engagement or attention, theeye track data and EEG data together demonstrate that the attention waslikely directed to the television.

The example system of FIG. 39 also includes a database 3914 for localstorage of raw data, processed data, result data, history logs,programming data from a media source, and/or any other type of data. Thetransmitter 3916 of the illustrated example communicates the data at anystage of processing and/or the results of the analysis from the headset3902 to a remote data facility 3920 and/or an electrical device 3922, asdisclosed in more detail below.

In some example implementations, the system 3900 is used to collectaudience measurement data. The example system 3900 determines if auser's neurological state indicates that the user is focused (e.g.,engaged with the media) while watching a certain media. The programidentifier 3906 identifies media to which the user is exposed. Theprogram identification can be done with any technology, for example, theprogram can be identified by collecting audio codes and/or signaturesusing a microphone on the headset to collect audio signals as disclosedin Thomas, U.S. Pat. No. 5,481,294. The program identifier 3906 collectsdata concerning the media, such as, for example, a television show, anadvertisement, a movie, a news clip, radio program, a web page, or anyother media and identifies the media (e.g., content or advertisement)based on the collected data and/or forwards the collected data toanother device to perform the identification.

In the collection of audience measurement data, the example system 3900gathers EEG data from the EEG sensors 3904 of the headset 3902. Thesystem gathers eye tracking data from the eye tracking sensor 3910 todetermine which direction the user is gazing during the media broadcast.The attention evaluator 3912 uses data from the EEG sensor 3904 and theeye tracker sensor 3910 to determine if a user paying attention to themedia. For example, if the EEG sensors 3904 detect brain waves (i.e.,electrical activity) indicative of increased thought, and the eyetracking sensor 3910 determines that the user is looking at the TV, theattention evaluator 3912 will output a signal that the user is focusedand immersed in that particular media program being broadcast. However,if the program identifier 3906 determines a certain program is beingpresented, and the EEG sensors 3904 indicate decreasing brain activity,or if the eye tracker senor 3910 determines the user is not looking atthe TV, then the attention evaluator 3912 will output a signal that theuser is not focused or immersed on that particular media program.

Data reflected of the user paying attention, the user not payingattention, or the user in a state of semi-involvement with the programand the identity of the program are storable in the database 3914 andtransmittable by the transmitter 3916 to an output including, forexample, a remote data facility 3920. Raw data, processed data, ahistory log or an indicator of audience measurement also may betransmitted to the remote data facility 3920 for collection. The remotedata facility 3920 may be, for example, a marketing company, a broadcastcompany, an entertainment studio, a television network and/or any otherorganization that might benefit from or otherwise desire to know whenusers are and/or are not focused on broadcast programs and what thoseprograms are. In some examples, the headset 3902 is communicativelycoupled to the remote data facility 3920 via a communication channel3924 such as common telephone line, a landline, an internet connection,radio waves, and/or any other communication technology capable ofsending signals. This example allows broadcasting companies and/ormarketing personnel to analyze which programs people are watching, whenthey are watching the programs and/or when they are focused during thebroadcast.

In another example implementation, the example system 3900 and headset3902 operate as a direct neural interface or brain-machine interface(BMI) that is to generate an input for an electrical device 3922 suchas, for example, a television, a radio, a computer mouse, a computerkeyboard, a remote control, a microwave, an application interface and/orother devices. The input signal for the electrical device 3922 is basedon data from the EEG sensor 3904 and/or the eye tracker sensor 3910 ofthe headset 3902. For example, the eye tracker sensor 3910 determinesthat the user is gazing at a certain area of his/her computer and theEEG sensors 3904 detect electrical activity indicative of focus. Thesystem 3900 used to control the electrical device 3922 uses specific EEGsignatures that trigger control including, for example, signatures inthe somatosensory system that are focal over the sensorimotor cortexcontralateral to movement and include changes in mu (e.g., 10-14 Hz) andbeta (e.g., 15-30 Hz) rhythms. Based on the EEG and eye tracking data,the remote action evaluator 3908 of the headset 3902 determines that theuser wants to move his or her cursor (i.e., mouse) to a different regionof the computer screen. The remote action evaluator 3908 sends a signalvia the transmitter 3916 to the electrical device 3922 to move thecursor on the screen. In another example, the remote action evaluator3908 analyzes data from the EEG sensor 3904 and determines that a userwants to change a volume level on the television. The remote actionevaluator 3908 transmits a signal via the transmitter 3916 to theelectrical device 3922 (i.e., the television or cable receiver) tochange the volume level. In the example shown, the headset 3902 iscommunicatively coupled to the electrical device 3922 via acommunication line 3926, which may be a hard wire or wirelesscommunication technology such as, for example, any of the communicationlinks discussed herein. In some examples, the remote action evaluatordevelops signals to conduct a plurality of other functions, such as, forexample, muting a television, changing a channel, powering a television,computer or other device on/off, opening a specific program on acomputer, setting a microwave, making a musical selection, operating aremote control device, operating a stereo in an automobile, operating alight switch, answering a phone, operating a DVR (digital videorecorder) and/or video-on-demand and/or any other function whichtypically involves the user pressing a button on a device or a remotecontrol of the device. EEG signals including changes in somatosensory muand beta rhythms are also used in other brain machine interfaceapplications including, for example, driving a wheelchair, controlling asmall robot, controlling exoskeletal devices on paralyzed limbs and/orother functions.

While example manner of implementing the system 3900 has beenillustrated in FIG. 39, one or more of the elements, processes and/ordevices illustrated in FIG. 39 may be combined, divided, re-arranged,omitted, eliminated and/or implemented in any other way. Further, theexample program identifier 3906, the example remote action evaluator3908, the example attention evaluator 3912, the example database 3914,the example transmitter 3916, the example remote data facility 3920, theexample electrical device 3922 and/or, more generally, the examplesystem 3900 of FIG. 39 may be implemented by hardware, software,firmware and/or any combination of hardware, software and/or firmware.Thus, for example, the example program identifier 3906, the exampleremote action evaluator 3908, the example attention evaluator 3912, theexample database 3914, the example transmitter 3916, the example remotedata facility 3920, the example electrical device 3922 and/or, moregenerally, the example system 3900 of FIG. 39 could be implemented byone or more circuit(s), programmable processor(s), application specificintegrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s))and/or field programmable logic device(s) (FPLD(s)), etc. When any ofthe apparatus or system claims of this patent are read to cover a purelysoftware and/or firmware implementation, at least one of the exampleprogram identifier 3906, the example remote action evaluator 3908, theexample attention evaluator 3912, the example database 3914, the exampletransmitter 3916, the example remote data facility 3920 or the exampleelectrical device 3922 are hereby expressly defined to include hardwareand/or a tangible computer readable medium such as a memory, DVD, CD,etc. storing the software and/or firmware. Further still, the examplesystem 3900 of FIG. 39 may include one or more elements, processesand/or devices in addition to, or instead of, those illustrated in FIG.39, and/or may include more than one of any or all of the illustratedelements, processes and devices.

FIGS. 40-44 are flowcharts representative, at least in part, of examplemachine readable instructions that may be executed to implement theexample headsets 100, 2300, 3400, 3812, 3902 and/or example systems3600, 3700, 3800, 3900. In the examples of FIGS. 40-44, the machinereadable instructions include a program for execution by a processorsuch as the processor 4512 shown in the example processing platform 4500discussed below in connection with FIG. 45. The program may be embodiedin software stored on a tangible computer readable medium such as aCD-ROM, a floppy disk, a hard drive, a digital versatile disk (DVD), ora memory associated with the processor 4512, but the entire programand/or parts thereof could alternatively be executed by a device otherthan the processor 4512 and/or embodied in firmware or dedicatedhardware. Further, although the example program is described withreference to the flowcharts illustrated in FIG. 40-44, many othermethods of implementing the example headsets 100, 2300, 3400, 3812, 3902and/or example systems 3600, 3700, 3800, 3900 may alternatively be used.For example, the order of execution of the blocks may be changed, and/orsome of the blocks described may be changed, eliminated, or combined.

As mentioned above, the example processes of FIGS. 40-44 may beimplemented, at least in part, using coded instructions (e.g., computerreadable instructions) stored on a tangible computer readable mediumsuch as a hard disk drive, a flash memory, a read-only memory (ROM), acompact disk (CD), a digital versatile disk (DVD), a cache, arandom-access memory (RAM) and/or any other storage media in whichinformation is stored for any duration (e.g., for extended time periods,permanently, brief instances, for temporarily buffering, and/or forcaching of the information). As used herein, the term tangible computerreadable medium is expressly defined to include any type of computerreadable storage medium and to exclude propagating signals. Additionallyor alternatively, the example processes of FIGS. 40-44 may beimplemented, at least in part, using coded instructions (e.g., computerreadable instructions) stored on a non-transitory computer readablemedium such as a hard disk drive, a flash memory, a read-only memory, acompact disk, a digital versatile disk, a cache, a random-access memoryand/or any other storage media in which information is stored for anyduration (e.g., for extended time periods, permanently, brief instances,for temporarily buffering, and/or for caching of the information). Asused herein, the term non-transitory computer readable medium isexpressly defined to include any type of computer readable medium and toexclude propagating signals.

FIG. 40 is a flowchart illustrating an example process of analyzing EEGdata (block 4000) collected from the example headsets 100, 2300, 3400,3812, 3902 and implemented by the example system 3600 of FIG. 36. Theexample headsets 100, 2300, 3400, 3812, 3902 have a plurality ofelectrodes that contact the scalp of a subject to receive electricalsignals from the subject's brain. The example process of analyzing EEGdata (4000) includes reading the EEG signals from the electrodes (block4002). In the illustrated example, the signals are converted from ananalog signal to a digital signal (block 4004). In some examples, theanalog-to-digital conversion takes place in a processing unit, such as,for example, the processing unit 3604 of the example system 3600. Inother examples, the analog-to-digital conversion takes place adjacentthe electrodes within the headset to convert the signal as close to thesource as possible.

In the illustrated example, the signals are conditioned (block 4006) toimprove the usefulness of the signals and the accessibility of the datacontained therein. For example, as disclosed above, the conditioning mayinclude amplifying the signals and/or filtering the signals (e.g., witha band pass filter). The signals are analyzed (block 4008) to, forexample, determine a mental state of the subject, a health condition, anengagement with media as an audience member, an input desire for anelectrical device and/or otherwise in accordance with the teachings ofthis disclosure.

In the illustrated example, the signals are transmitted to an output(block 4010), such as, for example, the output 3618 of the examplesystem 3600. Example modes of output are detailed above including, forexample, sounding an alarm, displaying a message and/or other alert on ascreen, issuing a report to a local and/or remote computer and/or anyother suitable output. In addition, the output may include the wired orwireless communications detailed herein. After the output (block 4010),the example process (4000) ends (block 4012).

FIG. 41 is a flowchart illustrating an example process of improving EEGsignal quality (block 4100) collected, for example, from one or more ofthe example headsets 100, 2300, 3400, 3812, 3902 and implemented by theexample system 3700 of FIG. 37. The example headsets 100, 2300, 3400,3812, 3902 include a plurality of electrodes (i.e., input channels) incontact with a head of a subject to receive electrical signals from thesubject's brain. In some examples, the example process of improvingsignal quality (4100) is implemented by a processor located at theheadset, such as, for example, in the second housing 128 of the headset100 shown in FIGS. 1-3. In other examples, the example process ofimproving signal quality (4100) occurs at a remote site, such as, forexample, a handheld device, a local computer, a remote server and/oranother suitable device.

The example process (4100) includes receiving signals from one or moreinput channel(s) (e.g., electrode(s)) (block 4102). In some examples,the analyzer 3712 of the system 3700 receives the signals from the inputchannels for analysis. One or more properties of one or more of thesignals are evaluated (block 4104). For example, the signals areevaluated to determine signal strength, amplitude, signal-to-noiseratio, duration and/or other characteristics in accordance with theteachings of this disclosure.

In the illustrated example process (4100), one or more of the signalsare conditioned (block 4106) to improve signal quality. In someexamples, conditioning the signals enhances the quality of the signalsto an acceptable level such that the signal is usable. In otherexamples, signal conditioning may not provide sufficient improvement toa signal. The example process (4100) also includes selecting one or moresignals to use, one or more signals to ignore and two or more signals tomerge (block 4108). As disclosed above, two or more signals may bemerged by shorting one of the signals, coupling the electrodes providingthe signals in parallel and/or averaging two or more signals, whichlowers the impedance and improves signal quality as detailed above. Theexample process (4100) improves signal quality by selecting thosesignal(s) to use and by ignoring the signals of poor quality. After theselection of valuable and/or improved signals (block 4108), the exampleprocesses of improving signal quality (4100) ends (block 4110), and thesignals and contained therein may be used in other processes such as,for example, the example analysis process (4000) of FIG. 40.

FIG. 42 is a flowchart illustrating an example process of conductingat-home patient monitoring and treatment (block 4200) using the exampleheadsets 100, 2300, 3400, 3812, 3902 and implemented by the examplesystem 3800 of FIG. 38. The example headsets 100, 2300, 3400, 3812,3902, as disclosed above, have a plurality of electrodes that contactthe scalp of a subject to receive electrical signals from the subject'sbrain. In some examples, the headsets 100, 2300, 3400, 3812, 3902 areworn by a subject for in-home monitoring, treatment and/or diagnosis ofa medical condition, to detect a life-threatening situation, toascertain patient compliance with a prescribed medical regime and/orother suitable applications in accordance with the teachings of thisdisclosure.

The example process (4200) includes gathering signals from theelectrodes or other suitable sensors (block 4202). As discussed above,the in-home patient monitoring system may incorporate not only the EEGreadings from the example headsets, but also other biometric,neurological and/or physiological systems to monitor, treat and/ordiagnosis medical conditions of an in-home patient. One or more of thesignals are analyzed (block 4204) to determine a mental/physical stateof the in-home patient. The signals may be analyzed, for example, withan analyzer or a processor such as the processor 134 disclosed above inthe second housing 128 of the headset 100 shown in FIGS. 1-3. One ormore of the signals may be conditioned and filtered in accordance withthe teachings of this disclosure such as, for example, as disclosed inthe example process (4000) of FIG. 40 and/or the example process (4100)of FIG. 41.

The example process (4200) determines whether the signals, an analysisof the signals or a notice related to the signals (e.g., such as analarm and/or other suitable communication) should be sent to a remotefacility (block 4206). The remote facility may be, for example, adoctor's office, a hospital, a clinic, a laboratory, an archive, aresearch facility and/or any other diagnostic facility. For example, ifthe signals indicate the occurrence of or an imminent occurrence of aheart attack, a stroke, an epileptic seizure and/or a fall, the exampleprocess (4200) determines that the signals, analysis or a notice shouldbe sent to the remote facility (block 4206), and the example process(4200) sends the signals and/or notice or alarm to the remote facility(block 4208). After sending a communication to the remote facility(block 4208), the example process (4200) may end (block 4218) orcontinue monitoring of the subject by gathering signals from the sensors(block 4202).

If the example process (4200) determines that the signals, analysis ornotice is not to be sent to a remote facility (block 4206), the exampleprocess (4200) determines if an output signal is to be produced (block4210) (such as, for example, to warn a patient of a condition or remindhim or her of an activity as disclosed in this patent). If an outputsignal is not to be produced (block 4210) (such as, for example, thesignals indicate that the patient's condition is normal and/or the datais otherwise benign), the example process may end (block 4218) orcontinue monitoring of the subject by gathering signals from the sensors(block 4202).

If the example process (4200) determines that an output signal should beproduced (block 4210), multiple types of outputs may be producedincluding any suitable output disclosed herein such as, for example,prompting a user for input (block 4212). As discussed above, patientsoften experience difficulty tracking and/or recalling their day-to-dayactivities. If the analysis indicates a certain spike in the readingoccurred, the output signal (block 4210) may prompt the user for input(block 4212) as to what he/she was doing just prior to the spike.

In another example, the output signal (block 4210) administersauto-delivery of medicine (block 4214). For example, if a patient isdiabetic, he/she may require continuous glucose and blood pressuremonitoring. The process may automatically deliver a dosage of medicineto the patient if his/her reading requires (e.g., the signals indicatethat a medical dosage is needed).

In another example, the output signal (block 4210) generates a signal(block 4216) such as a light, a sound, a display and/or any other outputis used, for example, to alert a patient of a need to seek medicalattention, to take a dosage of medicine, to start an activity, to stopan activity, to eat something and/or any other suitable warning and/orcommand. After producing one or more output(s) (blocks 4212, 4214,4216), the example process (4200) may end (block 4218) or continuemonitoring of the subject by gathering signals from the sensors (block4202).

FIG. 43 is a flowchart illustrating an example process of evaluating auser's attention to a program and/or manipulating one or more electricaldevice(s) (block 4300) using the example headsets 100, 2300, 3400, 3812,3900 and implemented by the example system 3900 of FIG. 39. The exampleheadsets 100, 2300, 3400, 3812, 3900 include a plurality of electrodesto receive electrical signals from the brain for processing inaccordance with the example process (4300). The example process (4300)illustrates the utility of EEG data and other physiological data (e.g.,eye tracking data) for multiple purposes.

The example process (4300) includes gathering the signals from the EEGsensors (e.g., electrodes and/or input channels) (block 4302). Data fromthese signals is used to determine attention, memory, focus and/or otherneurological states. The example process (4300) also includes gatheringsignals from an eye tracking sensor (block 4304). As discussed above,the eye tracking data may be used to corroborate the EEG data and bothsets of data (e.g., EEG and eye tracking) may be used to determine aneurological state of a user (block 4306).

In an example implementation, the neurological state of a user (block4306) is useful for audience measurement. For example, if a user islooking in the direction of a television and his or her EEG dataindicates that he or she is in a state of engagement or attention, theeye tracking data and EEG data together demonstrate that the user ispaying attention to the program. The example process (4300) alsoidentifies what media or program the user is exposed to (block 4308).For example, the process (4300) may collect audio codes and/orsignatures using a microphone and/or using any other device inaccordance with the teachings of this disclosure. Based on the collecteddata, the example process (4300) identifies the program or media towhich the use is exposed (block 4308). In the illustrated example, datareflecting whether the user is paying attention and to what program theuser is or is not paying attention to, is transmitted to a remotefacility (block 4310). As discussed above, the remote facility may be amarketing company, a broadcast company or any other organization thatmight benefit from or otherwise desire to know when users are and/or arenot focused on broadcast programs. After the results are sent (block4310), the example process (4300) may end (block 4316).

In another example implementation, the neurological state of a user(block 4306) is useful for evaluating whether a user wishes tomanipulate a device (block 4312) including, for example, an electricaldevice, as disclosed above. For example, the EEG data and eye trackingdata may indicate a user is gazing at a certain area of his/her computerand/or that the user has an increased level of focus. The exampleprocess (4300) determines that the user wants to control the device(e.g., computer) by, for example, opening a new application and/ormoving a cursor. If the example process (4300) determines that a userwants to control a device (block 4312), the example process (4300)transmits a signal to the device (block 4314) to effect the desiredcontrol of the device as disclosed above. After the control signal istransmitted (block 4314), the example process (4300) may end (block4316).

FIG. 44 is a flowchart illustrating an example process of gathering andanalyzing EEG data (block 4400) that may be implemented, for example,with any of the headsets and/or systems disclosed herein. The exampleprocess (4400) begins with placing a headset on a subject's head (block4402). The example headset, as disclosed above, has a plurality ofadjustable bands that extend over the head of a user. The headset mayinclude three, four, five, or ten or more individual bands. In someexamples, the headset may include less bands such as, for example, oneor two. The bands are removably and rotatably coupled on each end to afirst housing and a second housing. Each of the bands includes aplurality of electrodes for reading electrical activity along the scalpof a user. The headset may be oriented such that the first housing isnear a right ear of a user and the second housing is near a left ear ofthe user. The user can rotate the individual bands toward the inion (theprojection of the occipital bone) or the nasion (the intersection of thefrontal bone and two nasal bones) to position the electrodes in specificlocations for measuring electrical activity (block 4404). Each of thebands also comprises an elastic strap. The user may adjust the elasticstraps on the bands to tighten the bands and press the electrodes on thebands down toward and against the user's head (block 4406). The user maytighten a back strap to secure the headset on the user's head (block4408).

The example process (4400) also includes reading EEG data such as, forexample, from one of more of the electrode(s) disclosed above (block4410). Raw signals from the electrodes may then be conditioned (block4412) with hardware, firmware and/or software components, such as, anA/D converter, an amplifier and/or one or more filters as disclosedabove. In some examples, one or more of the conditioning components maybe incorporated into a housing on a headset, into the individualadjustable bands, at each individual electrode and/or at a remoteprocessor. In some example implementations of the example process(4400), a user determines if it is desirable to rotate the headset 900(or any other suitable angle) for additional or alternative EEG data(block 4414). With a rotated headset, the bands traverse from theforehead to the back of the head. Such an orientation may be desired,for example, to obtain midline readings. If the user wishes to acquireadditional data in the orthogonal position (block 4414), he or sherotates the headset 90° (block 4416) and repositions and adjusts thebands as explained above (blocks 4402-4408). With the headset positionedfor the desired reading (block 4414) the conditioned signals areanalyzed (block 4418).

The example process (4400) also includes determining if one or more ofthe electrode(s) needs to be or should be adjusted (block 4420). Anelectrode should be adjusted, for example, to obtain a clearer signal.If one or more the electrode(s) are to be adjusted, the example process(4400) includes determining if the adjustment is to a physicaladjustment or a non-physical adjustment (4422). If the adjustment is aphysical adjustment (4422), control of the example process (4400)returns to block 4404, and the appropriate band(s) are rotated intoposition and/or the elongated strap(s) or straps are adjusted (blocks4406-4408). If the electrode(s) are to be non-physically adjusted(4422), the example process (4400) includes virtually moving and/orshorting one or more of the electrode(s) (block 4424), as detailedabove. With the adjusted electrode(s), the example process (4400)returns to continue to read the EEG signal (block 4410), and the exampleprocess (4400) continues.

If the electrode(s) do not need to be further adjusted (block 4424),then the signals are analyzed to produce an output assessment or mentalpicture (block 4426). As disclosed above, the output assessment ormental picture may determine, for example, the neurological state of theperson. For example, as provided in examples disclosed above, the EEGdata includes multiple frequency bands, which can be analyzed todetermine, for example, if person has high concentration, is sleeping,is depressed, is happy, is calm and/or any other emotional and/orneurological state as disclosed above. The output assessment/mentalpicture provides insights into the thoughts, emotions and/or health ofthe person.

The example method 4400 also includes determining if the output is to beused with one or more additional application(s) (block 4428). If theoutput is to be used with one or more additional application(s) such as,for example, medical applications, audience measurements, remote devicecontrol and/or any other suitable application as disclosed herein, suchapplications are performed (block 4430). The example process (4400) alsodetermines if monitoring of EEG data should continue (block 4432). Iffurther monitoring is to be conducted, control of the method returns toblock 4410, and EEG signal data is read. If further monitoring is not tobe conducted, then the example method 4400 ends (block 4434).

FIG. 45 is a block diagram of an example processing platform 4500capable of executing the one or more of the instructions of FIGS. 40-44to implement one or more portions of the apparatus and/or systems ofFIGS. 1, 23, 34 and 36-39. The processing platform 4500 can be, forexample a processor in a headset, a server, a personal computer, and/orany other type of computing device.

The system 4500 of the instant example includes a processor 4512. Forexample, the processor 4512 can be implemented by one or moremicroprocessors or controllers from any desired family or manufacturer.

The processor 4512 includes a local memory 4513 (e.g., a cache) and isin communication with a main memory including a volatile memory 4514 anda non-volatile memory 4516 via a bus 4518. The volatile memory 4514 maybe implemented by Synchronous Dynamic Random Access Memory (SDRAM),Dynamic Random Access Memory (DRAM), RAMBUS Dynamic Random Access Memory(RDRAM) and/or any other type of random access memory device. Thenon-volatile memory 4516 may be implemented by flash memory and/or anyother desired type of memory device. Access to the main memory 4514,4516 is controlled by a memory controller.

The processing platform 4500 also includes an interface circuit 4520.The interface circuit 4520 may be implemented by any type of interfacestandard, such as an Ethernet interface, a universal serial bus (USB),and/or a PCI express interface.

One or more input devices 4522 are connected to the interface circuit4520. The input device(s) 4522 permit a user to enter data and commandsinto the processor 4512. The input device(s) can be implemented by, forexample, an electrode, a physiological sensor, a keyboard, a mouse, atouchscreen, a track-pad, a trackball, isopoint and/or a voicerecognition system.

One or more output devices 4524 are also connected to the interfacecircuit 4520. The output devices 4524 can be implemented, for example,by display devices (e.g., a liquid crystal display and/or speakers). Theinterface circuit 4520, thus, typically includes a graphics driver.

The interface circuit 4520 also includes a communication device (e.g.,transmitter 3616, 3916) such as a modem or network interface card tofacilitate exchange of data with external computers via a network 4526(e.g., an Ethernet connection, a digital subscriber line (DSL), atelephone line, coaxial cable, a cellular telephone system, etc.).

The processing platform 4500 also includes one or more mass storagedevices 4528 for storing software and data. Examples of such massstorage devices 4528 include floppy disk drives, hard drive disks,compact disk drives and digital versatile disk (DVD) drives. The massstorage device 4628 may implement the local storage device 3612, 3822,3914.

The coded instructions 4532 of FIGS. 40-44 may be stored in the massstorage device 4528, in the volatile memory 4514, in the non-volatilememory 4516, and/or on a removable storage medium such as a CD or DVD.

Although certain example apparatus have been described herein, the scopeof coverage of this patent is not limited thereto. On the contrary, thispatent covers all methods, apparatus, and articles of manufacture fairlyfalling within the scope of the appended claims either literally orunder the doctrine of equivalents.

1. (canceled)
 2. A headset comprising: a support to be disposed at leastpartially around ahead of a subject; a first housing carried by thesupport, the first housing to be disposed on a first side of the head ofthe subject; a second housing carried by the support, the second housingto be disposed on a second side of the head of the subject opposite thefirst side; and a band adjustably coupled to the first housing and thesecond housing, the band including: an electrode strip to be disposedover the head of the subject such that a first end of the electrodestrip is adjacent the first housing and a second end of the electrodestrip is adjacent the second housing; and a strap extending through anaperture in the electrode strip, the strap adjustably coupled to thefirst housing to adjust a position of the electrode strip relative tothe head of the subject.
 3. The headset of claim 2, wherein the apertureis a first aperture, the first aperture near the first end of theelectrode strip, a second aperture in the electrode strip near thesecond end of the electrode strip.
 4. The headset of claim 2, whereinthe first end of the electrode strip is spaced apart from the firsthousing and the second end of the electrode strip is spaced apart fromthe second housing.
 5. The headset of claim 2, wherein the strap isslidable along the electrode strip.
 6. The headset of claim 2, whereinthe band is a first band and the electrode strip is a first electrodestrip, further including a second band adjustably coupled to the firsthousing and the second housing, the second band including a secondelectrode strip to be disposed over the head of the subject such that afirst end of the second electrode strip is adjacent the first housingand a second end of the second electrode strip is adjacent the secondhousing.
 7. The headset of claim 6, wherein the strap is a first strap,the second band including a second strap.
 8. The headset of claim 7,wherein the second strap extends through an aperture in the secondelectrode strip.
 9. The headset of claim 8, wherein the second strap isadjustably coupled to the first housing to adjust a position of thesecond electrode strip relative to the head of the subject.
 10. Theheadset of claim 9, further including a third band adjustably coupled tothe first housing and the second housing, the third band including: athird electrode strip to be disposed over the head of the subject suchthat a first end of the third electrode strip is adjacent the firsthousing and a second end of the third electrode strip is adjacent thesecond housing; and a third strap extending through an aperture in thethird electrode strip, the third strap adjustably coupled to the firsthousing to adjust a position of the third electrode strip relative tothe head of the subject.
 11. The headset of claim 8, wherein the secondstrap is adjustably coupled to the second housing to adjust a positionof the second electrode strip relative to the head of the subject. 12.The headset of claim 2, wherein the band includes electrodes carried bythe electrode strip.
 13. The headset of claim 12, wherein the electrodesare removably coupled to the electrode strip.
 14. The headset of claim12, wherein the electrodes include pin electrodes.
 15. The headset ofclaim 12, wherein the band includes a printed circuit board (PCB) moldedinto the electrode strip, the electrodes communicatively coupled to thePCB.
 16. The headset of claim 12, further including a processor to:analyze signals gathered by the electrodes; determine a mental state ofthe subject based on the signals; and cause a notification to bepresented to the subject based on the mental state.
 17. The headset ofclaim 16, wherein the processor is to: analyze the signals over time;determine a baseline of mental activity of the user based on the signalsover time; and determine a change in mental state of the user based on adeviation from the baseline.
 18. The headset of claim 2, wherein theband includes a first electrode on a first side of the electrode stripand a second electrode on a second side of the electrode strip, andwherein tightening of the strap increases a distance between the firstelectrode and the second electrode.
 19. The headset of claim 2, whereinthe band includes a ring electrode and a pin electrode carried by theelectrode strip.
 20. The headset of claim 2, wherein the band includes aplurality of protrusions along the electrode strip to maintain alignmentof the strap.
 21. The headset of claim 2, wherein the support includesan elastic band.